PM: sleep: Call dpm_async_fn() directly in each suspend phase

Simplify the system-wide suspend of devices by invoking dpm_async_fn()
directly from the main loop in each suspend phase instead of using an
additional wrapper function for running it.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM: sleep: Move devices to new lists earlier in each suspend phase

During a system-wide suspend of devices, dpm_noirq_suspend_devices(),
dpm_suspend_late() and dpm_suspend() move devices from one list to
another. They do it with each device after its PM callback in the
given suspend phase has run or has been scheduled for asynchronous
execution, in case it is deleted from the current list in the
meantime.

However, devices can be moved to a new list before invoking their PM
callbacks (which usually is the case for the devices whose callbacks
are executed asynchronously anyway), because doing so does not affect
the ordering of that list. In either case, each device is moved to
the new list after the previous device has been moved to it or gone
away, and if a device is removed, it does not matter which list it is
in at that point, because deleting an entry from a list does not change
the ordering of the other entries in it.

Accordingly, modify the functions mentioned above to move devices to
new lists without waiting for their PM callbacks to run regardless of
whether or not they run asynchronously.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM: sleep: Move some assignments from under a lock

The async_error and pm_transition variables are set under dpm_list_mtx
in multiple places in the system-wide device PM core code, which is
unnecessary and confusing, so rearrange the code so that the variables
in question are set before acquiring the lock.

While at it, add some empty code lines around locking to improve the
consistency of the code.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM: sleep: stats: Log errors right after running suspend callbacks

The error logging and failure statistics updates are carried out in two
places in each system-wide device suspend phase, which is unnecessary
code duplication, so do that in one place in each phase, right after
invoking device suspend callbacks.

While at it, add "noirq" or "late" to the "async" string printed when
the failing device callback in the "noirq" or "late" suspend phase,
respectively, was run asynchronously.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM: sleep: stats: Call dpm_save_failed_step() at most once per phase

If the handling of two or more devices fails in one suspend-resume
phase, it should be counted once in the statistics which is not
guaranteed to happen during system-wide resume of devices due to
the possible asynchronous execution of device callbacks.

Address this by using the async_error static variable during system-wide
device resume to indicate that there has been a device resume error and
the given suspend-resume phase should be counted as failing.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM: sleep: stats: Define suspend_stats next to the code using it

It is not necessary to define struct suspend_stats in a header file and the
suspend_stats variable in the core device system-wide PM code. They both
can be defined in kernel/power/main.c, next to the sysfs and debugfs code
accessing suspend_stats, which can be static.

Modify the code in question in accordance with the above observation and
replace the static inline functions manipulating suspend_stats with
regular ones defined in kernel/power/main.c.

While at it, move the enum suspend_stat_step to the end of suspend.h which
is a more suitable place for it.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM: sleep: stats: Use an array of step failure counters

Instead of using a set of individual struct suspend_stats fields
representing suspend step failure counters, use an array of counters
indexed by enum suspend_stat_step for this purpose, which allows
dpm_save_failed_step() to increment the appropriate counter
automatically, so that its callers don't need to do that directly.

It also allows suspend_stats_show() to carry out a loop over the
counters array to print their values.

Because the counters cannot become negative, use unsigned int for
representing them.

The only user-observable impact of this change is a different
ordering of entries in the suspend_stats debugfs file which is not
expected to matter.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM: sleep: Relocate two device PM core functions

Move is_async() and dpm_async_fn() in the PM core to a more suitable
place.

No functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>

PM: sleep: Simplify dpm_suspended_list walk in dpm_resume()

Notice that devices can be moved to dpm_prepared_list before running
their resume callbacks, in analogy with dpm_noirq_resume_devices() and
dpm_resume_early(), because doing so will not affect the final ordering
of that list.

Namely, if a device is the first dpm_suspended_list entry while
dpm_list_mtx is held, it has not been removed so far and it cannot be
removed until dpm_list_mtx is released, so moving it to dpm_prepared_list
at that point is valid. If it is removed later, while its resume
callback is running, it will be deleted from dpm_prepared_list without
changing the ordering of the other devices in that list.

Accordingly, rearrange the while () loop in dpm_resume() to move
devices to dpm_prepared_list before running their resume callbacks and
implify the locking and device reference counting in it.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>

PM: sleep: Restore asynchronous device resume optimization

Before commit 7839d0078e0d ("PM: sleep: Fix possible deadlocks in core
system-wide PM code"), the resume of devices that were allowed to resume
asynchronously was scheduled before starting the resume of the other
devices, so the former did not have to wait for the latter unless
functional dependencies were present.

Commit 7839d0078e0d removed that optimization in order to address a
correctness issue, but it can be restored with the help of a new device
power management flag, so do that now.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>

PM: sleep: Fix possible deadlocks in core system-wide PM code

It is reported that in low-memory situations the system-wide resume core
code deadlocks, because async_schedule_dev() executes its argument
function synchronously if it cannot allocate memory (and not only in
that case) and that function attempts to acquire a mutex that is already
held. Executing the argument function synchronously from within
dpm_async_fn() may also be problematic for ordering reasons (it may
cause a consumer device's resume callback to be invoked before a
requisite supplier device's one, for example).

Address this by changing the code in question to use
async_schedule_dev_nocall() for scheduling the asynchronous
execution of device suspend and resume functions and to directly
run them synchronously if async_schedule_dev_nocall() returns false.

Link: https://lore.kernel.org/linux-pm/ZYvjiqX6EsL15moe@perf/
Reported-by: Youngmin Nam <youngmin.nam@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Tested-by: Youngmin Nam <youngmin.nam@samsung.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Cc: 5.7+ <stable@vger.kernel.org> # 5.7+: 6aa09a5bccd8 async: Split async_schedule_node_domain()
Cc: 5.7+ <stable@vger.kernel.org> # 5.7+: 7d4b5d7a37bd async: Introduce async_schedule_dev_nocall()
Cc: 5.7+ <stable@vger.kernel.org> # 5.7+

PM: core: Remove unnecessary (void *) conversions

Assignments from pointer variables of type (void *) do not require
explicit type casts, so remove such type cases from the code in
drivers/base/power/main.c where applicable.

Signed-off-by: Li zeming <zeming@nfschina.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: core: keep irq flags in device_pm_check_callbacks()

The function device_pm_check_callbacks() can be called under the spin
lock (in the reported case it happens from genpd_add_device() ->
dev_pm_domain_set(), when the genpd uses spinlocks rather than mutexes.

However this function uncoditionally uses spin_lock_irq() /
spin_unlock_irq(), thus not preserving the CPU flags. Use the
irqsave/irqrestore instead.

The backtrace for the reference:
[ 2.752010] ------------[ cut here ]------------
[ 2.756769] raw_local_irq_restore() called with IRQs enabled
[ 2.762596] WARNING: CPU: 4 PID: 1 at kernel/locking/irqflag-debug.c:10 warn_bogus_irq_restore+0x34/0x50
[ 2.772338] Modules linked in:
[ 2.775487] CPU: 4 PID: 1 Comm: swapper/0 Tainted: G S 5.17.0-rc6-00384-ge330d0d82eff-dirty #684
[ 2.781384] Freeing initrd memory: 46024K
[ 2.785839] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 2.785841] pc : warn_bogus_irq_restore+0x34/0x50
[ 2.785844] lr : warn_bogus_irq_restore+0x34/0x50
[ 2.785846] sp : ffff80000805b7d0
[ 2.785847] x29: ffff80000805b7d0 x28: 0000000000000000 x27: 0000000000000002
[ 2.785850] x26: ffffd40e80930b18 x25: ffff7ee2329192b8 x24: ffff7edfc9f60800
[ 2.785853] x23: ffffd40e80930b18 x22: ffffd40e80930d30 x21: ffff7edfc0dffa00
[ 2.785856] x20: ffff7edfc09e3768 x19: 0000000000000000 x18: ffffffffffffffff
[ 2.845775] x17: 6572206f74206465 x16: 6c696166203a3030 x15: ffff80008805b4f7
[ 2.853108] x14: 0000000000000000 x13: ffffd40e809550b0 x12: 00000000000003d8
[ 2.860441] x11: 0000000000000148 x10: ffffd40e809550b0 x9 : ffffd40e809550b0
[ 2.867774] x8 : 00000000ffffefff x7 : ffffd40e809ad0b0 x6 : ffffd40e809ad0b0
[ 2.875107] x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 0000000000000000
[ 2.882440] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff7edfc03a8000
[ 2.889774] Call trace:
[ 2.892290] warn_bogus_irq_restore+0x34/0x50
[ 2.896770] _raw_spin_unlock_irqrestore+0x94/0xa0
[ 2.901690] genpd_unlock_spin+0x20/0x30
[ 2.905724] genpd_add_device+0x100/0x2d0
[ 2.909850] __genpd_dev_pm_attach+0xa8/0x23c
[ 2.914329] genpd_dev_pm_attach_by_id+0xc4/0x190
[ 2.919167] genpd_dev_pm_attach_by_name+0x3c/0xd0
[ 2.924086] dev_pm_domain_attach_by_name+0x24/0x30
[ 2.929102] psci_dt_attach_cpu+0x24/0x90
[ 2.933230] psci_cpuidle_probe+0x2d4/0x46c
[ 2.937534] platform_probe+0x68/0xe0
[ 2.941304] really_probe.part.0+0x9c/0x2fc
[ 2.945605] __driver_probe_device+0x98/0x144
[ 2.950085] driver_probe_device+0x44/0x15c
[ 2.954385] __device_attach_driver+0xb8/0x120
[ 2.958950] bus_for_each_drv+0x78/0xd0
[ 2.962896] __device_attach+0xd8/0x180
[ 2.966843] device_initial_probe+0x14/0x20
[ 2.971144] bus_probe_device+0x9c/0xa4
[ 2.975092] device_add+0x380/0x88c
[ 2.978679] platform_device_add+0x114/0x234
[ 2.983067] platform_device_register_full+0x100/0x190
[ 2.988344] psci_idle_init+0x6c/0xb0
[ 2.992113] do_one_initcall+0x74/0x3a0
[ 2.996060] kernel_init_freeable+0x2fc/0x384
[ 3.000543] kernel_init+0x28/0x130
[ 3.004132] ret_from_fork+0x10/0x20
[ 3.007817] irq event stamp: 319826
[ 3.011404] hardirqs last enabled at (319825): [<ffffd40e7eda0268>] __up_console_sem+0x78/0x84
[ 3.020332] hardirqs last disabled at (319826): [<ffffd40e7fd6d9d8>] el1_dbg+0x24/0x8c
[ 3.028458] softirqs last enabled at (318312): [<ffffd40e7ec90410>] _stext+0x410/0x588
[ 3.036678] softirqs last disabled at (318299): [<ffffd40e7ed1bf68>] __irq_exit_rcu+0x158/0x174
[ 3.045607] ---[ end trace 0000000000000000 ]---

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: Add device name to suspend_report_result()

Currently, suspend_report_result() prints only function information.

If any driver uses a common PM function, nobody knows who exactly
called the failing function.

A device pinter is needed to recognize the failing device.

For example:

PM: dpm_run_callback(): pnp_bus_suspend+0x0/0x10 returns 0
PM: dpm_run_callback(): pci_pm_suspend+0x0/0x150 returns 0

become after the change:

serial 00:05: PM: dpm_run_callback(): pnp_bus_suspend+0x0/0x10 returns 0
pci 0000:00:01.3: PM: dpm_run_callback(): pci_pm_suspend+0x0/0x150 returns 0

Signed-off-by: Youngjin Jang <yj84.jang@samsung.com>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: Fix error handling in dpm_prepare()

Commit 2aa36604e824 ("PM: sleep: Avoid calling put_device() under
dpm_list_mtx") forgot to update the while () loop termination
condition to also break the loop if error is nonzero, which
causes the loop to become infinite if device_prepare() returns
an error for one device.

Add the missing !error check.

Fixes: 2aa36604e824 ("PM: sleep: Avoid calling put_device() under dpm_list_mtx")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reported-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Cc: All applicable <stable@vger.kernel.org>

PM: sleep: Avoid calling put_device() under dpm_list_mtx

It is generally unsafe to call put_device() with dpm_list_mtx held,
because the given device's release routine may carry out an action
depending on that lock which then may deadlock, so modify the
system-wide suspend and resume of devices to always drop dpm_list_mtx
before calling put_device() (and adjust white space somewhat while
at it).

For instance, this prevents the following splat from showing up in
the kernel log after a system resume in certain configurations:

[ 3290.969514] ======================================================
[ 3290.969517] WARNING: possible circular locking dependency detected
[ 3290.969519] 5.15.0+ #2420 Tainted: G S
[ 3290.969523] ------------------------------------------------------
[ 3290.969525] systemd-sleep/4553 is trying to acquire lock:
[ 3290.969529] ffff888117ab1138 ((wq_completion)hci0#2){+.+.}-{0:0}, at: flush_workqueue+0x87/0x4a0
[ 3290.969554]
but task is already holding lock:
[ 3290.969556] ffffffff8280fca8 (dpm_list_mtx){+.+.}-{3:3}, at: dpm_resume+0x12e/0x3e0
[ 3290.969571]
which lock already depends on the new lock.

[ 3290.969573]
the existing dependency chain (in reverse order) is:
[ 3290.969575]
-> #3 (dpm_list_mtx){+.+.}-{3:3}:
[ 3290.969583] __mutex_lock+0x9d/0xa30
[ 3290.969591] device_pm_add+0x2e/0xe0
[ 3290.969597] device_add+0x4d5/0x8f0
[ 3290.969605] hci_conn_add_sysfs+0x43/0xb0 [bluetooth]
[ 3290.969689] hci_conn_complete_evt.isra.71+0x124/0x750 [bluetooth]
[ 3290.969747] hci_event_packet+0xd6c/0x28a0 [bluetooth]
[ 3290.969798] hci_rx_work+0x213/0x640 [bluetooth]
[ 3290.969842] process_one_work+0x2aa/0x650
[ 3290.969851] worker_thread+0x39/0x400
[ 3290.969859] kthread+0x142/0x170
[ 3290.969865] ret_from_fork+0x22/0x30
[ 3290.969872]
-> #2 (&hdev->lock){+.+.}-{3:3}:
[ 3290.969881] __mutex_lock+0x9d/0xa30
[ 3290.969887] hci_event_packet+0xba/0x28a0 [bluetooth]
[ 3290.969935] hci_rx_work+0x213/0x640 [bluetooth]
[ 3290.969978] process_one_work+0x2aa/0x650
[ 3290.969985] worker_thread+0x39/0x400
[ 3290.969993] kthread+0x142/0x170
[ 3290.969999] ret_from_fork+0x22/0x30
[ 3290.970004]
-> #1 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}:
[ 3290.970013] process_one_work+0x27d/0x650
[ 3290.970020] worker_thread+0x39/0x400
[ 3290.970028] kthread+0x142/0x170
[ 3290.970033] ret_from_fork+0x22/0x30
[ 3290.970038]
-> #0 ((wq_completion)hci0#2){+.+.}-{0:0}:
[ 3290.970047] __lock_acquire+0x15cb/0x1b50
[ 3290.970054] lock_acquire+0x26c/0x300
[ 3290.970059] flush_workqueue+0xae/0x4a0
[ 3290.970066] drain_workqueue+0xa1/0x130
[ 3290.970073] destroy_workqueue+0x34/0x1f0
[ 3290.970081] hci_release_dev+0x49/0x180 [bluetooth]
[ 3290.970130] bt_host_release+0x1d/0x30 [bluetooth]
[ 3290.970195] device_release+0x33/0x90
[ 3290.970201] kobject_release+0x63/0x160
[ 3290.970211] dpm_resume+0x164/0x3e0
[ 3290.970215] dpm_resume_end+0xd/0x20
[ 3290.970220] suspend_devices_and_enter+0x1a4/0xba0
[ 3290.970229] pm_suspend+0x26b/0x310
[ 3290.970236] state_store+0x42/0x90
[ 3290.970243] kernfs_fop_write_iter+0x135/0x1b0
[ 3290.970251] new_sync_write+0x125/0x1c0
[ 3290.970257] vfs_write+0x360/0x3c0
[ 3290.970263] ksys_write+0xa7/0xe0
[ 3290.970269] do_syscall_64+0x3a/0x80
[ 3290.970276] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 3290.970284]
other info that might help us debug this:

[ 3290.970285] Chain exists of:
(wq_completion)hci0#2 --> &hdev->lock --> dpm_list_mtx

[ 3290.970297] Possible unsafe locking scenario:

[ 3290.970299] CPU0 CPU1
[ 3290.970300] ---- ----
[ 3290.970302] lock(dpm_list_mtx);
[ 3290.970306] lock(&hdev->lock);
[ 3290.970310] lock(dpm_list_mtx);
[ 3290.970314] lock((wq_completion)hci0#2);
[ 3290.970319]
*** DEADLOCK ***

[ 3290.970321] 7 locks held by systemd-sleep/4553:
[ 3290.970325] #0: ffff888103bcd448 (sb_writers#4){.+.+}-{0:0}, at: ksys_write+0xa7/0xe0
[ 3290.970341] #1: ffff888115a14488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x103/0x1b0
[ 3290.970355] #2: ffff888100f719e0 (kn->active#233){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x10c/0x1b0
[ 3290.970369] #3: ffffffff82661048 (autosleep_lock){+.+.}-{3:3}, at: state_store+0x12/0x90
[ 3290.970384] #4: ffffffff82658ac8 (system_transition_mutex){+.+.}-{3:3}, at: pm_suspend+0x9f/0x310
[ 3290.970399] #5: ffffffff827f2a48 (acpi_scan_lock){+.+.}-{3:3}, at: acpi_suspend_begin+0x4c/0x80
[ 3290.970416] #6: ffffffff8280fca8 (dpm_list_mtx){+.+.}-{3:3}, at: dpm_resume+0x12e/0x3e0
[ 3290.970428]
stack backtrace:
[ 3290.970431] CPU: 3 PID: 4553 Comm: systemd-sleep Tainted: G S 5.15.0+ #2420
[ 3290.970438] Hardware name: Dell Inc. XPS 13 9380/0RYJWW, BIOS 1.5.0 06/03/2019
[ 3290.970441] Call Trace:
[ 3290.970446] dump_stack_lvl+0x44/0x57
[ 3290.970454] check_noncircular+0x105/0x120
[ 3290.970468] ? __lock_acquire+0x15cb/0x1b50
[ 3290.970474] __lock_acquire+0x15cb/0x1b50
[ 3290.970487] lock_acquire+0x26c/0x300
[ 3290.970493] ? flush_workqueue+0x87/0x4a0
[ 3290.970503] ? __raw_spin_lock_init+0x3b/0x60
[ 3290.970510] ? lockdep_init_map_type+0x58/0x240
[ 3290.970519] flush_workqueue+0xae/0x4a0
[ 3290.970526] ? flush_workqueue+0x87/0x4a0
[ 3290.970544] ? drain_workqueue+0xa1/0x130
[ 3290.970552] drain_workqueue+0xa1/0x130
[ 3290.970561] destroy_workqueue+0x34/0x1f0
[ 3290.970572] hci_release_dev+0x49/0x180 [bluetooth]
[ 3290.970624] bt_host_release+0x1d/0x30 [bluetooth]
[ 3290.970687] device_release+0x33/0x90
[ 3290.970695] kobject_release+0x63/0x160
[ 3290.970705] dpm_resume+0x164/0x3e0
[ 3290.970710] ? dpm_resume_early+0x251/0x3b0
[ 3290.970718] dpm_resume_end+0xd/0x20
[ 3290.970723] suspend_devices_and_enter+0x1a4/0xba0
[ 3290.970737] pm_suspend+0x26b/0x310
[ 3290.970746] state_store+0x42/0x90
[ 3290.970755] kernfs_fop_write_iter+0x135/0x1b0
[ 3290.970764] new_sync_write+0x125/0x1c0
[ 3290.970777] vfs_write+0x360/0x3c0
[ 3290.970785] ksys_write+0xa7/0xe0
[ 3290.970794] do_syscall_64+0x3a/0x80
[ 3290.970803] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 3290.970811] RIP: 0033:0x7f41b1328164
[ 3290.970819] Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 80 00 00 00 00 8b 05 4a d2 2c 00 48 63 ff 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 55 53 48 89 d5 48 89 f3 48 83
[ 3290.970824] RSP: 002b:00007ffe6ae21b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 3290.970831] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f41b1328164
[ 3290.970836] RDX: 0000000000000004 RSI: 000055965e651070 RDI: 0000000000000004
[ 3290.970839] RBP: 000055965e651070 R08: 000055965e64f390 R09: 00007f41b1e3d1c0
[ 3290.970843] R10: 000000000000000a R11: 0000000000000246 R12: 0000000000000004
[ 3290.970846] R13: 0000000000000001 R14: 000055965e64f2b0 R15: 0000000000000004

Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: Fix runtime PM based cpuidle support

In the cpuidle-psci case, runtime PM in combination with the generic PM
domain (genpd), may be used when entering/exiting a shared idlestate. More
precisely, genpd relies on runtime PM to be enabled for the attached device
(in this case it belongs to a CPU), to properly manage the reference
counting of its PM domain.

This works fine most of the time, but during system suspend in
dpm_suspend_late(), the PM core disables runtime PM for all devices. Beyond
this point, calls to pm_runtime_get_sync() to runtime resume a device may
fail and therefore it could also mess up the reference counting in genpd.

To fix this problem, let's call wake_up_all_idle_cpus() in
dpm_suspend_late(), prior to disabling runtime PM. In this way a device
that belongs to a CPU, becomes runtime resumed through cpuidle-psci and
stays like that, because the runtime PM usage count has been bumped in
device_prepare().

Diagnosed-by: Maulik Shah <mkshah@codeaurora.org>
Suggested-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: Pause cpuidle later and resume it earlier during system transitions

Commit 8651f97bd951 ("PM / cpuidle: System resume hang fix with
cpuidle") that introduced cpuidle pausing during system suspend
did that to work around a platform firmware issue causing systems
to hang during resume if CPUs were allowed to enter idle states
in the system suspend and resume code paths.

However, pausing cpuidle before the last phase of suspending
devices is the source of an otherwise arbitrary difference between
the suspend-to-idle path and other system suspend variants, so it is
cleaner to do that later, before taking secondary CPUs offline (it
is still safer to take secondary CPUs offline with cpuidle paused,
though).

Modify the code accordingly, but in order to avoid code duplication,
introduce new wrapper functions, pm_sleep_disable_secondary_cpus()
and pm_sleep_enable_secondary_cpus(), to combine cpuidle_pause()
and cpuidle_resume(), respectively, with the handling of secondary
CPUs during system-wide transitions to sleep states.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>

PM: suspend: Do not pause cpuidle in the suspend-to-idle path

It is pointless to pause cpuidle in the suspend-to-idle path,
because it is going to be resumed in the same path later and
pausing it does not serve any particular purpose in that case.

Rework the code to avoid doing that.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>

PM: sleep: Do not let "syscore" devices runtime-suspend during system transitions

There is no reason to allow "syscore" devices to runtime-suspend
during system-wide PM transitions, because they are subject to the
same possible failure modes as any other devices in that respect.

Accordingly, change device_prepare() and device_complete() to call
pm_runtime_get_noresume() and pm_runtime_put(), respectively, for
"syscore" devices too.

Fixes: 057d51a1268f ("Merge branch 'pm-sleep'")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 3.10+ <stable@vger.kernel.org> # 3.10+
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM: sleep: core: Avoid setting power.must_resume to false

There are variables(power.may_skip_resume and dev->power.must_resume)
and DPM_FLAG_MAY_SKIP_RESUME flags to control the resume of devices after
a system wide suspend transition.

Setting the DPM_FLAG_MAY_SKIP_RESUME flag means that the driver allows
its "noirq" and "early" resume callbacks to be skipped if the device
can be left in suspend after a system-wide transition into the working
state. PM core determines that the driver's "noirq" and "early" resume
callbacks should be skipped or not with dev_pm_skip_resume() function by
checking power.may_skip_resume variable.

power.must_resume variable is getting set to false in __device_suspend()
function without checking device's DPM_FLAG_MAY_SKIP_RESUME settings.
In problematic scenario, where all the devices in the suspend_late
stage are successful and some device can fail to suspend in
suspend_noirq phase. So some devices successfully suspended in suspend_late
stage are not getting chance to execute __device_suspend_noirq()
to set dev->power.must_resume variable to true and not getting
resumed in early_resume phase.

Add a check for device's DPM_FLAG_MAY_SKIP_RESUME flag before
setting power.must_resume variable in __device_suspend function.

Fixes: 6e176bf8d461 ("PM: sleep: core: Do not skip callbacks in the resume phase")
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: Use ktime_us_delta() in initcall_debug_report()

Use ktime_us_delta() to make the debug log more precise instead of
shifting the return value of ktime_to_ns() applied to a ktime_sub()
result by 10 bit positions to the right.

Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
[ rjw: Changelog rewrite, subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: Use dev_printk() when possible

Use dev_printk() when possible to make messages more consistent with other
device-related messages.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: Add dev_wakeup_path() helper

Add dev_wakeup_path() helper to avoid to spread
dev->power.wakeup_path test in drivers.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: Print driver flags for all devices during suspend/resume

Currently there are 4 driver flags to control system suspend/resume
behavior: DPM_FLAG_NO_DIRECT_COMPLETE, DPM_FLAG_SMART_PREPARE,
DPM_FLAG_SMART_SUSPEND and DPM_FLAG_MAY_SKIP_RESUME.

Print these flags during suspend/resume so as to get a brief
understanding of the expected behavior of each device, and to
facilitate suspend/resume debugging/tuning.

To enable this tracing:
echo 'file drivers/base/power/main.c +p' >
/sys/kernel/debug/dynamic_debug/control

Signed-off-by: Chen Yu <yu.c.chen@intel.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: remove unreachable break

A break following a return statement is pointless, so drop it.

Signed-off-by: Tom Rix <trix@redhat.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: core: Fix the handling of pending runtime resume requests

It has been reported that system-wide suspend may be aborted in the
absence of any wakeup events due to unforseen interactions of it with
the runtume PM framework.

One failing scenario is when there are multiple devices sharing an
ACPI power resource and runtime-resume needs to be carried out for
one of them during system-wide suspend (for example, because it needs
to be reconfigured before the whole system goes to sleep). In that
case, the runtime-resume of that device involves turning the ACPI
power resource "on" which in turn causes runtime-resume requests
to be queued up for all of the other devices sharing it. Those
requests go to the runtime PM workqueue which is frozen during
system-wide suspend, so they are not actually taken care of until
the resume of the whole system, but the pm_runtime_barrier()
call in __device_suspend() sees them and triggers system wakeup
events for them which then cause the system-wide suspend to be
aborted if wakeup source objects are in active use.

Of course, the logic that leads to triggering those wakeup events is
questionable in the first place, because clearly there are cases in
which a pending runtime resume request for a device is not connected
to any real wakeup events in any way (like the one above). Moreover,
it is racy, because the device may be resuming already by the time
the pm_runtime_barrier() runs and so if the driver doesn't take care
of signaling the wakeup event as appropriate, it will be lost.
However, if the driver does take care of that, the extra
pm_wakeup_event() call in the core is redundant.

Accordingly, drop the conditional pm_wakeup_event() call fron
__device_suspend() and make the latter call pm_runtime_barrier()
alone. Also modify the comment next to that call to reflect the new
code and extend it to mention the need to avoid unwanted interactions
between runtime PM and system-wide device suspend callbacks.

Fixes: 1e2ef05bb8cf8 ("PM: Limit race conditions between runtime PM and system sleep (v2)")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Utkarsh H Patel <utkarsh.h.patel@intel.com>
Tested-by: Utkarsh H Patel <utkarsh.h.patel@intel.com>
Tested-by: Pengfei Xu <pengfei.xu@intel.com>
Cc: All applicable <stable@vger.kernel.org>

kernel: rename show_stack_loglvl() => show_stack()

Now the last users of show_stack() got converted to use an explicit log
level, show_stack_loglvl() can drop it's redundant suffix and become once
again well known show_stack().

Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200418201944.482088-51-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

power: use show_stack_loglvl()

Aligning with other watchdog messages just before panic - use KERN_EMERG.

Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Link: http://lkml.kernel.org/r/20200418201944.482088-47-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

PM: sleep: core: Rename DPM_FLAG_LEAVE_SUSPENDED

Rename DPM_FLAG_LEAVE_SUSPENDED to DPM_FLAG_MAY_SKIP_RESUME which
matches its purpose more closely.

No functional impact.

Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de> # for I2C
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>

PM: sleep: core: Rename DPM_FLAG_NEVER_SKIP

Rename DPM_FLAG_NEVER_SKIP to DPM_FLAG_NO_DIRECT_COMPLETE which
matches its purpose more closely.

No functional impact.

Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> # for PCI parts
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>

PM: sleep: core: Rename dev_pm_smart_suspend_and_suspended()

Because all callers of dev_pm_smart_suspend_and_suspended use it only
for checking whether or not to skip driver suspend callbacks for a
device, rename it to dev_pm_skip_suspend() in analogy with
dev_pm_skip_resume().

No functional impact.

Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>

PM: sleep: core: Rename dev_pm_may_skip_resume()

The name of dev_pm_may_skip_resume() may be easily confused with the
power.may_skip_resume flag which is not checked by that function, so
rename the former as dev_pm_skip_resume().

No functional impact.

Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>

PM: sleep: core: Rework the power.may_skip_resume handling

Because the power.may_skip_resume device status bit is taken
into account in combination with the DPM_FLAG_LEAVE_SUSPENDED
driver flag, it can be set to 'true' for all devices in the
"suspend" phase of a suspend-resume cycle, so do that.

Then, neither the PM core nor the middle-layer (sybsystem) code
handling it needs to set it to 'true' any more and it just has
to be cleared if there is a reason to avoid skipping the "noirq"
and "early" resume callbacks provided by the driver, so update
the code in question accordingly.

Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>

PM: sleep: core: Do not skip callbacks in the resume phase

The current code in device_resume_noirq() causes the entire early
resume and resume phases of device suspend to be skipped for
devices for which the noirq resume phase have been skipped (due
to the LEAVE_SUSPENDED flag being set) on the premise that those
devices should stay in runtime-suspend after system-wide resume.

However, that may not be correct in two situations. First, the
middle layer (subsystem) noirq resume callback may be missing for
a given device, but its early resume callback may be present and it
may need to do something even if it decides to skip the driver
callback. Second, if the device's wakeup settings were adjusted
in the suspend phase without resuming the device (that was in
runtime suspend at that time), they most likely need to be
adjusted again in the resume phase and so the driver callback
in that phase needs to be run.

For the above reason, modify the core to allow the middle layer
->resume_late callback to run even if its ->resume_noirq callback
is missing (and the core has skipped the driver-level callback
in that phase) and to allow all device callbacks to run in the
resume phase. Also make the core set the PM-runtime status of
devices with SMART_SUSPEND set whose resume callbacks are not
skipped to "active" in the "noirq" resume phase and update the
affected subsystems (PCI and ACPI) accordingly.

After this change, middle-layer (subsystem) callbacks will always
be invoked in all phases of system suspend and resume and driver
callbacks will always run in the prepare, suspend, resume, and
complete phases for all devices.

For devices with SMART_SUSPEND set, driver callbacks will be
skipped in the late and noirq phases of system suspend if those
devices remain in runtime suspend in __device_suspend_late().
Driver callbacks will also be skipped for them during the
noirq and early phases of the "thaw" transition related to
hibernation in that case.

Setting LEAVE_SUSPENDED means that the driver allows its callbacks
to be skipped in the noirq and early phases of system resume, but
some additional conditions need to be met for that to happen (among
other things, the power.may_skip_resume flag needs to be set for the
device during system suspend for the driver callbacks to be skipped
during the subsequent resume transition).

For all devices with SMART_SUSPEND set whose driver callbacks are
invoked during system resume, the PM-runtime status will be set to
"active" (by the core).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>

PM: sleep: core: Switch back to async_schedule_dev()

Commit 8b9ec6b73277 ("PM core: Use new async_schedule_dev command")
introduced a new function for better performance.

However commit f2a424f6c613 ("PM / core: Introduce dpm_async_fn()
helper") went back to the non-optimized version, async_schedule().

So switch back to the sync_schedule_dev() to improve performance

Fixes: f2a424f6c613 ("PM / core: Introduce dpm_async_fn() helper")
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: core: Fold functions into their callers

Fold four functions in the PM core that each have only one caller
now into their callers.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>

PM: sleep: core: Simplify the SMART_SUSPEND flag handling

The code to handle the SMART_SUSPEND driver PM flag is hard to follow
and somewhat inconsistent with respect to devices without middle-layer
(subsystem) callbacks.

Namely, for those devices the core takes the role of a middle layer
in providing the expected ordering of execution of callbacks (under
the assumption that the drivers setting SMART_SUSPEND can reuse their
PM-runtime callbacks directly for system-wide suspend). To that end,
it prevents driver ->suspend_late and ->suspend_noirq callbacks from
being executed for devices that are still runtime-suspended in
__device_suspend_late(), because running the same callback funtion
that was previously run by PM-runtime for them may be invalid.

However, it does that only for devices without any middle-layer
callbacks for the late/noirq/early suspend/resume phases even
though it would be simpler and more consistent to skip the
driver-lavel callbacks for all devices with SMART_SUSPEND set
that are runtime-suspended in __device_suspend_late().

Simplify the code in accordance with the above observation.

Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>

PM: sleep: core: Drop racy and redundant checks from device_prepare()

Alan Stern points out that the WARN_ON() check in device_prepare()
is racy (because the PM-runtime API can be disabled briefly for any
device at any time and system suspend can start at any time too) and
the pm_runtime_suspended() check in the computation of the
direct_complete flag value is redundant (because it will be
repeated later anyway).

Drop both these checks accordingly.

Reported-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: sleep: core: Use built-in RCU list checking

This patch passes the cond argument to list_for_each_entry_rcu()
to fix the following false-positive lockdep warnings:
(with CONFIG_PROVE_RCU_LIST = y)

[ 330.302784] =============================
[ 330.302789] WARNING: suspicious RCU usage
[ 330.302796] 5.6.0-rc1+ #5 Not tainted
[ 330.302801] -----------------------------
[ 330.302808] drivers/base/power/main.c:326 RCU-list traversed in non-reader section!!

[ 330.303303] =============================
[ 330.303307] WARNING: suspicious RCU usage
[ 330.303311] 5.6.0-rc1+ #5 Not tainted
[ 330.303315] -----------------------------
[ 330.303319] drivers/base/power/main.c:1698 RCU-list traversed in non-reader section!!

[ 331.934969] =============================
[ 331.934971] WARNING: suspicious RCU usage
[ 331.934973] 5.6.0-rc1+ #5 Not tainted
[ 331.934975] -----------------------------
[ 331.934977] drivers/base/power/main.c:1238 RCU-list traversed in non-reader section!!

[ 332.467772] WARNING: suspicious RCU usage
[ 332.467775] 5.6.0-rc1+ #5 Not tainted
[ 332.467775] -----------------------------
[ 332.467778] drivers/base/power/main.c:269 RCU-list traversed in non-reader section!!

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: core: Fix handling of devices deleted during system-wide resume

If a device is deleted by one of its system-wide resume callbacks
(for example, because it does not appear to be present or accessible
any more) along with its children, the resume of the children may
continue leading to use-after-free errors and other issues
(potentially).

Namely, if the device's children are resumed asynchronously, their
resume may have been scheduled already before the device's callback
runs and so the device may be deleted while dpm_wait_for_superior()
is being executed for them. The memory taken up by the parent device
object may be freed then while dpm_wait() is waiting for the parent's
resume callback to complete, which leads to a use-after-free.
Moreover, the resume of the children is really not expected to
continue after they have been unregistered, so it must be terminated
right away in that case.

To address this problem, modify dpm_wait_for_superior() to check
if the target device is still there in the system-wide PM list of
devices and if so, to increment its parent's reference counter, both
under dpm_list_mtx which prevents device_del() running for the child
from dropping the parent's reference counter prematurely.

If the device is not present in the system-wide PM list of devices
any more, the resume of it cannot continue, so check that again after
dpm_wait() returns, which means that the parent's callback has been
completed, and pass the result of that check to the caller of
dpm_wait_for_superior() to allow it to abort the device's resume
if it is not there any more.

Link: https://lore.kernel.org/linux-pm/1579568452-27253-1-git-send-email-chanho.min@lge.com
Reported-by: Chanho Min <chanho.min@lge.com>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM: sleep: Drop dpm_noirq_begin() and dpm_noirq_end()

Note that after previous changes dpm_noirq_begin() and
dpm_noirq_end() each have only one caller, so move the code from
them to their respective callers and drop them.

Also note that dpm_noirq_resume_devices() and
dpm_noirq_suspend_devices() need not be exported any more, so make
them both static.

This change is not expected to alter functionality.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>

PM: sleep: Simplify suspend-to-idle control flow

After commit 33e4f80ee69b ("ACPI / PM: Ignore spurious SCI wakeups
from suspend-to-idle") the "noirq" phases of device suspend and
resume may run for multiple times during suspend-to-idle, if there
are spurious system wakeup events while suspended. However, this
is complicated and fragile and actually unnecessary.

The main reason for doing this is that on some systems the EC may
signal system wakeup events (power button events, for example) as
well as events that should not cause the system to resume (spurious
system wakeup events). Thus, in order to determine whether or not
a given event signaled by the EC while suspended is a proper system
wakeup one, the EC GPE needs to be dispatched and to start with that
was achieved by allowing the ACPI SCI action handler to run, which
was only possible after calling resume_device_irqs().

However, dispatching the EC GPE this way turned out to take too much
time in some cases and some EC events might be missed due to that, so
commit 68e22011856f ("ACPI: EC: Dispatch the EC GPE directly on
s2idle wake") started to dispatch the EC GPE right after a wakeup
event has been detected, so in fact the full ACPI SCI action handler
doesn't need to run any more to deal with the wakeups coming from the
EC.

Use this observation to simplify the suspend-to-idle control flow
so that the "noirq" phases of device suspend and resume are each
run only once in every suspend-to-idle cycle, which is reported to
significantly reduce power drawn by some systems when suspended to
idle (by allowing them to reach a deep platform-wide low-power state
through the suspend-to-idle flow). [What appears to happen is that
the "noirq" resume of devices after a spurious EC wakeup brings some
devices into a state in which they prevent the platform from reaching
the deep low-power state going forward, even after a subsequent
"noirq" suspend phase, and on some systems the EC triggers such
wakeups already when the "noirq" suspend of devices is running for
the first time in the given suspend/resume cycle, so the platform
cannot reach the deep low-power state at all.]

First, make acpi_s2idle_wake() use the acpi_ec_dispatch_gpe() return
value to determine whether or not the wakeup may have been triggered
by the EC (in which case the system wakeup is canceled and ACPI
events are processed in order to determine whether or not the event
is a proper system wakeup one) and use rearm_wake_irq() (introduced
by a previous change) in it to rearm the ACPI SCI for system wakeup
detection in case the system will remain suspended.

Second, drop acpi_s2idle_sync(), which is not needed any more, and
the corresponding global platform suspend-to-idle callback.

Next, drop the pm_wakeup_pending() check (which is an optimization
only) from __device_suspend_noirq() to prevent it from returning
errors on system wakeups occurring before the "noirq" phase of
device suspend is complete (as in the case of suspend-to-idle it is
not known whether or not these wakeups are suprious at that point),
in order to avoid having to carry out a "noirq" resume of devices
on a spurious system wakeup.

Finally, change the code flow in s2idle_loop() to (1) run the
"noirq" suspend of devices once before starting the loop, (2) check
for spurious EC wakeups (via the platform ->wake callback) for the
first time before calling s2idle_enter(), and (3) run the "noirq"
resume of devices once after leaving the loop.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>

PM: sleep: Drop dev_pm_skip_next_resume_phases()

After recent hibernation-related changes, there are no more callers
of dev_pm_skip_next_resume_phases() except for the PM core itself
in which it is more straightforward to run the statements from
that function directly, so do that and drop it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

PM: sleep: Show how long dpm_suspend_start() and dpm_suspend_end() take

When debugging device driver power management code it is convenient to
know how much time is spent in the "suspend start" and "suspend end"
phases. Hence log the time spent in these phases.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Propagate dev->power.wakeup_path when no callbacks

The dev->power.direct_complete flag may become set in device_prepare() in
case the device don't have any PM callbacks (dev->power.no_pm_callbacks is
set). This leads to a broken behaviour, when there is child having wakeup
enabled and relies on its parent to be used in the wakeup path.

More precisely, when the direct complete path becomes selected for the
child in __device_suspend(), the propagation of the dev->power.wakeup_path
becomes skipped as well.

Let's address this problem, by checking if the device is a part the wakeup
path or has wakeup enabled, then prevent the direct complete path from
being used.

Reported-by: Loic Pallardy <loic.pallardy@st.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[ rjw: Comment cleanup ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Introduce dpm_async_fn() helper

When we want to execute device pm functions asynchronously, we'll
do the following for the device:

1) reinit_completion(&dev->power.completion);
2) Check if the device enables asynchronous suspend.
3) If necessary, execute the corresponding function asynchronously.

There are a lot of such repeated operations here, in fact we can avoid
this. So introduce dpm_async_fn() to have better code readability and
reuse.

And use this function to do some cleanup.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

treewide: Switch printk users from %pf and %pF to %ps and %pS, respectively

%pF and %pf are functionally equivalent to %pS and %ps conversion
specifiers. The former are deprecated, therefore switch the current users
to use the preferred variant.

The changes have been produced by the following command:

git grep -l '%p[fF]' | grep -v '^\(tools\|Documentation\)/' | \
while read i; do perl -i -pe 's/%pf/%ps/g; s/%pF/%pS/g;' $i; done

And verifying the result.

Link: http://lkml.kernel.org/r/20190325193229.23390-1-sakari.ailus@linux.intel.com
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: sparclinux@vger.kernel.org
Cc: linux-um@lists.infradead.org
Cc: xen-devel@lists.xenproject.org
Cc: linux-acpi@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: drbd-dev@lists.linbit.com
Cc: linux-block@vger.kernel.org
Cc: linux-mmc@vger.kernel.org
Cc: linux-nvdimm@lists.01.org
Cc: linux-pci@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Cc: linux-btrfs@vger.kernel.org
Cc: linux-f2fs-devel@lists.sourceforge.net
Cc: linux-mm@kvack.org
Cc: ceph-devel@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: David Sterba <dsterba@suse.com> (for btrfs)
Acked-by: Mike Rapoport <rppt@linux.ibm.com> (for mm/memblock.c)
Acked-by: Bjorn Helgaas <bhelgaas@google.com> (for drivers/pci)
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>

PM / core: fix kerneldoc comment for device_pm_wait_for_dev()

Rearrange comment to make the comment style consistent, the previous
function parameters are described first.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: fix kerneldoc comment for dpm_watchdog_handler()

This brings the kernel doc in line with the function signature.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers: base: power: add proper SPDX identifiers on files that did not have them.

There were a few files in the driver core power code that did not have
SPDX identifiers on them, so fix that up. At the same time, remove the
"free form" text that specified the license of the file, as that is
impossible for any tool to properly parse.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM: Add and use pr_fmt()

Prefix all printk/pr_<level> messages with "PM: " to make the
logging a bit more consistent.

Miscellanea:

o Convert a few printks to pr_<level>
o Whitespace to align to open parentheses
o Remove embedded "PM: " from pr_debugs as pr_fmt adds it

Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Add support to skip power management in device/driver model

All device objects in the driver model contain fields that control the
handling of various power management activities. However, it's not
always useful. There are few instances where pseudo devices are added
to the model just to take advantage of many other features like
kobjects, udev events, and so on. One such example is cpu devices and
their caches.

The sysfs for the cpu caches are managed by adding devices with cpu
as the parent in cpu_device_create() when secondary cpu is brought
online. Generally when the secondary CPUs are hotplugged back in as part
of resume from suspend-to-ram, we call cpu_device_create() from the cpu
hotplug state machine while the cpu device associated with that CPU is
not yet ready to be resumed as the device_resume() call happens bit
later. It's not really needed to set the flag is_prepared for cpu
devices as they are mostly pseudo device and hotplug framework deals
with state machine and not managed through the cpu device.

This often results in annoying warning when resuming:
Enabling non-boot CPUs ...
CPU1: Booted secondary processor
cache: parent cpu1 should not be sleeping
CPU1 is up
CPU2: Booted secondary processor
cache: parent cpu2 should not be sleeping
CPU2 is up
.... and so on.

So in order to fix these kind of errors, we could just completely avoid
doing any power management related initialisations and operations if
they are not used by these devices.

Add no_pm flags to indicate that the device doesn't require any sort of
PM activities and all of them can be completely skipped. We can use the
same flag to also avoid adding not used *power* sysfs entries for these
devices. For now, lets use this for cpu cache devices.

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / suspend: Print debug messages for device using direct-complete

Devices using the direct-complete optimization are not present it
debug messages printed by the core device suspend and resume code,
which sometimes makes it difficult to diagnose problems related to
them, so add debug messages for those devices.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM core: Use new async_schedule_dev command

Use the device specific version of the async_schedule commands to defer
various tasks related to power management. By doing this we should see a
slight improvement in performance as any device that is sensitive to
latency/locality in the setup will now be initializing on the node closest
to the device.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM: sleep: call devfreq suspend/resume

Devfreq framework supports suspend of its devices.
Call the the devfreq interface and allow devfreq devices
preserve/restore their states during suspend/resume.

Suggested-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Clear the direct_complete flag on errors

If __device_suspend() runs asynchronously (in which case the device
passed to it is in dpm_suspended_list at that point) and it returns
early on an error or pending wakeup, and the power.direct_complete
flag has been set for the device already, the subsequent
device_resume() will be confused by that and it will call
pm_runtime_enable() incorrectly, as runtime PM has not been
disabled for the device by __device_suspend().

To avoid that, clear power.direct_complete if __device_suspend()
is not going to disable runtime PM for the device before returning.

Fixes: aae4518b3124 (PM / sleep: Mechanism to avoid resuming runtime-suspended devices unnecessarily)
Reported-by: Al Cooper <alcooperx@gmail.com>
Tested-by: Al Cooper <alcooperx@gmail.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Cc: 3.16+ <stable@vger.kernel.org> # 3.16+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Fix direct_complete handling for devices with no callbacks

Commit 08810a4119aa (PM / core: Add NEVER_SKIP and SMART_PREPARE
driver flags) inadvertently prevented the power.direct_complete flag
from being set for devices without PM callbacks and with disabled
runtime PM which also prevents power.direct_complete from being set
for their parents. That led to problems including a resume crash on
HP ZBook 14u.

Restore the previous behavior by causing power.direct_complete to be
set for those devices again, but do that in a more direct way to
avoid overlooking that case in the future.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=199693
Fixes: 08810a4119aa (PM / core: Add NEVER_SKIP and SMART_PREPARE driver flags)
Reported-by: Thomas Martitz <kugel@rockbox.org>
Tested-by: Thomas Martitz <kugel@rockbox.org>
Cc: 4.15+ <stable@vger.kernel.org> # 4.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Johan Hovold <johan@kernel.org>

PM / core: Use dev_printk() and symbols in suspend/resume diagnostics

When we print diagnostic messages about suspend/resume, we have a device
pointer, so use dev_printk() to match other device-related things. Add the
function name, similar to initcall_debug output. E.g.,

- calling 0000:01:00.0+ @ 998, parent: 0000:00:1c.0
+ pci 0000:01:00.0: calling <something> @ 998, parent: 0000:00:1c.0

I wondered if this would break scripts/bootgraph.pl, but I don't think it
will because bootgraph.pl doesn't add any timing information to $start{}
after it sees "Write protecting the" or "Freeing unused kernel memory".

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Simplify initcall_debug_report() timing

initcall_debug_report() always called ktime_get(), even if we didn't
need the result.

Change it so we only call it when we're going to use the result, and
change initcall_debug_start() to follow the same style.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Remove unused initcall_debug_report() arguments

Commit e8bca479c3f2 (PM / sleep: trace events for device PM callbacks)
removed the only uses of "state" and "info" from initcall_debug_report().

Remove the now-unused arguments completely.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Propagate wakeup_path status flag in __device_suspend_late()

Currently the wakeup_path status flag becomes propagated from a child
device to its parent device at __device_suspend(). This allows a driver
dealing with a parent device to act on the flag from its ->suspend()
callback.

However, in situations when the wakeup_path status flag needs to be set
from a ->suspend_late() callback, its value doesn't get propagated to the
parent by the PM core. Let's address this limitation, by also propagating
the flag at __device_suspend_late().

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Re-structure code for clearing the direct_complete flag

To make the code more consistent, let's clear the parent's direct_complete
flag along with clearing it for suppliers, instead of as currently, when
propagating the wakeup_path flag to parents.

While changing this, let's take the opportunity to rename the affected
internal functions, to make them self-explanatory. Like this:

dpm_clear_suppliers_direct_complete -> dpm_clear_superiors_direct_complete
dpm_propagate_to_parent -> dpm_propagate_wakeup_to_parent

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Assign the wakeup_path status flag in __device_prepare()

The PM core in the device_prepare() phase, resets the wakeup_path status
flag to the value of device_may_wakeup(). This means if a ->prepare() or a
->suspend() callback for the device would update the device's wakeup
setting, this doesn't become reflected in the wakeup_path status flag.

In general this isn't a problem, because wakeup settings are not supposed
to be changed (via for example calling device_set_wakeup_enable()) during
any system wide suspend/resume phase. Nevertheless there are some users,
which can be considered as legacy, that don't conform to this behaviour.

These legacy cases should be corrected, however until that is done, let's
address the issue from the PM core, by moving the assignment of the
wakeup_path status flag to the __device_suspend() phase and after the
->suspend() callback has been invoked.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Direct DPM_FLAG_LEAVE_SUSPENDED handling

Make the PM core handle DPM_FLAG_LEAVE_SUSPENDED directly for
devices whose "noirq", "late" and "early" driver callbacks are
invoked directly by it.

Namely, make it skip all of the system-wide resume callbacks for
such devices with DPM_FLAG_LEAVE_SUSPENDED set if they are in
runtime suspend during the "noirq" phase of system-wide suspend
(or analogous) transitions or the system transition under way is
a proper suspend (rather than anything related to hibernation) and
the device's wakeup settings are compatible with runtime PM (that
is, the device cannot generate wakeup signals at all or it is
allowed to wake up the system from sleep).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Direct DPM_FLAG_SMART_SUSPEND optimization

Make the PM core avoid invoking the "late" and "noirq" system-wide
suspend (or analogous) callbacks provided by device drivers directly
for devices with DPM_FLAG_SMART_SUSPEND set that are in runtime
suspend during the "late" and "noirq" phases of system-wide suspend
(or analogous) transitions. That is only done for devices without
any middle-layer "late" and "noirq" suspend callbacks (to avoid
confusing the middle layer if there is one).

The underlying observation is that runtime PM is disabled for devices
during the "late" and "noirq" system-wide suspend phases, so if they
remain in runtime suspend from the "late" phase forward, it doesn't
make sense to invoke the "late" and "noirq" callbacks provided by
the drivers for them (arguably, the device is already suspended and
in the right state). Thus, if the remaining driver suspend callbacks
are to be invoked directly by the core, they can be skipped.

This change really makes it possible for, say, platform device
drivers to re-use runtime PM suspend and resume callbacks by
pointing ->suspend_late and ->resume_early, respectively (and
possibly the analogous hibernation-related callback pointers too),
to them without adding any extra "is the device already suspended?"
type of checks to the callback routines, as long as they will be
invoked directly by the core.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Add helpers for subsystem callback selection

Add helper routines to find and return a suitable subsystem callback
during the "noirq" phases of system suspend/resume (or analogous)
transitions as well as during the "late" phase of system suspend and
the "early" phase of system resume (or analogous) transitions.

The helpers will be called from additional sites going forward.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

PM / core: Use dev_pm_skip_next_resume_phases() internally

Make the PM core call dev_pm_skip_next_resume_phases() to skip the
"early resume" and "resume" phases of system-wide transitions to the
working state for a given device instead of clearing the relevant
status bits for it directly.

No intentional changes in functionality.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM / core: remove unneeded kallsyms include

The file was converted from print_fn_descriptor_symbol()
to %pF some time ago (c80cfb0406c01bb "vsprintf: use new
vsprintf symbolic function pointer format"). kallsyms does
not seem to be needed anymore.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Avoid excess pm_runtime_enable() calls in device_resume()

Middle-layer code doing suspend-time optimizations for devices with
the DPM_FLAG_SMART_SUSPEND flag set (currently, the PCI bus type and
the ACPI PM domain) needs to make the core skip ->thaw_early and
->thaw callbacks for those devices in some cases and it sets the
power.direct_complete flag for them for this purpose.

However, it turns out that setting power.direct_complete outside of
the PM core is a bad idea as it triggers an excess invocation of
pm_runtime_enable() in device_resume().

For this reason, provide a helper to clear power.is_late_suspended
and power.is_suspended to be invoked by the middle-layer code in
question instead of setting power.direct_complete and make that code
call the new helper.

Fixes: c4b65157aeef (PCI / PM: Take SMART_SUSPEND driver flag into account)
Fixes: 05087360fd7a (ACPI / PM: Take SMART_SUSPEND driver flag into account)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>

PM / core: Re-factor some code dealing with parents in __device_suspend()

Let's make the code a bit more readable by moving some of the code, which
deals with adjustments for parent devices in __device_suspend(), into its
own function.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Add LEAVE_SUSPENDED driver flag

Define and document a new driver flag, DPM_FLAG_LEAVE_SUSPENDED, to
instruct the PM core and middle-layer (bus type, PM domain, etc.)
code that it is desirable to leave the device in runtime suspend
after system-wide transitions to the working state (for example,
the device may be slow to resume and it may be better to avoid
resuming it right away).

Generally, the middle-layer code involved in the handling of the
device is expected to indicate to the PM core whether or not the
device may be left in suspend with the help of the device's
power.may_skip_resume status bit. That has to happen in the "noirq"
phase of the preceding system suspend (or analogous) transition.
The middle layer is then responsible for handling the device as
appropriate in its "noirq" resume callback which is executed
regardless of whether or not the device may be left suspended, but
the other resume callbacks (except for ->complete) will be skipped
automatically by the core if the device really can be left in
suspend.

The additional power.must_resume status bit introduced for the
implementation of this mechanisn is used internally by the PM core
to track the requirement to resume the device (which may depend on
its children etc).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PCI / PM: Take SMART_SUSPEND driver flag into account

Make the PCI bus type take DPM_FLAG_SMART_SUSPEND into account in its
system-wide PM callbacks and make sure that all code that should not
run in parallel with pci_pm_runtime_resume() is executed in the "late"
phases of system suspend, freeze and poweroff transitions.

[Note that the pm_runtime_suspended() check in pci_dev_keep_suspended()
is an optimization, because if is not passed, all of the subsequent
checks may be skipped and some of them are much more overhead in
general.]

Also use the observation that if the device is in runtime suspend
at the beginning of the "late" phase of a system-wide suspend-like
transition, its state cannot change going forward (runtime PM is
disabled for it at that time) until the transition is over and the
subsequent system-wide PM callbacks should be skipped for it (as
they generally assume the device to not be suspended), so add checks
for that in pci_pm_suspend_late/noirq(), pci_pm_freeze_late/noirq()
and pci_pm_poweroff_late/noirq().

Moreover, if pci_pm_resume_noirq() or pci_pm_restore_noirq() is
called during the subsequent system-wide resume transition and if
the device was left in runtime suspend previously, its runtime PM
status needs to be changed to "active" as it is going to be put
into the full-power state, so add checks for that too to these
functions.

In turn, if pci_pm_thaw_noirq() runs after the device has been
left in runtime suspend, the subsequent "thaw" callbacks need
to be skipped for it (as they may not work correctly with a
suspended device), so set the power.direct_complete flag for the
device then to make the PM core skip those callbacks.

In addition to the above add a core helper for checking if
DPM_FLAG_SMART_SUSPEND is set and the device runtime PM status is
"suspended" at the same time, which is done quite often in the new
code (and will be done elsewhere going forward too).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>

PM / core: Add SMART_SUSPEND driver flag

Define and document a SMART_SUSPEND flag to instruct bus types and PM
domains that the system suspend callbacks provided by the driver can
cope with runtime-suspended devices, so from the driver's perspective
it should be safe to leave devices in runtime suspend during system
suspend.

Setting that flag may also cause middle-layer code (bus types,
PM domains etc.) to skip invocations of the ->suspend_late and
->suspend_noirq callbacks provided by the driver if the device
is in runtime suspend at the beginning of the "late" phase of
the system-wide suspend transition, in which case the driver's
system-wide resume callbacks may be invoked back-to-back with
its ->runtime_suspend callback, so the driver has to be able to
cope with that too.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM / core: Add NEVER_SKIP and SMART_PREPARE driver flags

The motivation for this change is to provide a way to work around
a problem with the direct-complete mechanism used for avoiding
system suspend/resume handling for devices in runtime suspend.

The problem is that some middle layer code (the PCI bus type and
the ACPI PM domain in particular) returns positive values from its
system suspend ->prepare callbacks regardless of whether the driver's
->prepare returns a positive value or 0, which effectively prevents
drivers from being able to control the direct-complete feature.
Some drivers need that control, however, and the PCI bus type has
grown its own flag to deal with this issue, but since it is not
limited to PCI, it is better to address it by adding driver flags at
the core level.

To that end, add a driver_flags field to struct dev_pm_info for flags
that can be set by device drivers at the probe time to inform the PM
core and/or bus types, PM domains and so on on the capabilities and/or
preferences of device drivers. Also add two static inline helpers
for setting that field and testing it against a given set of flags
and make the driver core clear it automatically on driver remove
and probe failures.

Define and document two PM driver flags related to the direct-
complete feature: NEVER_SKIP and SMART_PREPARE that can be used,
respectively, to indicate to the PM core that the direct-complete
mechanism should never be used for the device and to inform the
middle layer code (bus types, PM domains etc) that it can only
request the PM core to use the direct-complete mechanism for
the device (by returning a positive value from its ->prepare
callback) if it also has been requested by the driver.

While at it, make the core check pm_runtime_suspended() when
setting power.direct_complete so that it doesn't need to be
checked by ->prepare callbacks.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

PM / core: Fix kerneldoc comments of four functions

Fix the kerneldoc comments of __device_suspend_noirq(),
__device_suspend_late() and __device_suspend() where the function
names in kerneldoc don't match the actual names of the functions.

Also fix the device_resume_noirq() kerneldoc comment which mentions
"early resume" instead of "noirq resume" incorrectly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

timer: Remove init_timer_on_stack() in favor of timer_setup_on_stack()

Remove uses of init_timer_on_stack() with open-coded function and data
assignments that could be expressed using timer_setup_on_stack(). Several
were removed from the stack entirely since there was a one-to-one mapping
of parent structure to timer, those are switched to using timer_setup()
instead. All related callbacks were adjusted to use from_timer().

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Cc: Petr Mladek <pmladek@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Kalle Valo <kvalo@qca.qualcomm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: linux1394-devel@lists.sourceforge.net
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: linux-s390@vger.kernel.org
Cc: linux-wireless@vger.kernel.org
Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>
Cc: linux-scsi@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ursula Braun <ubraun@linux.vnet.ibm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Harish Patil <harish.patil@cavium.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Michael Reed <mdr@sgi.com>
Cc: Manish Chopra <manish.chopra@cavium.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-pm@vger.kernel.org
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Mark Gross <mark.gross@intel.com>
Cc: linux-watchdog@vger.kernel.org
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: netdev@vger.kernel.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Link: https://lkml.kernel.org/r/1507159627-127660-4-git-send-email-keescook@chromium.org

PM / core: Drop legacy class suspend/resume operations

There are no classes using the legacy suspend/resume operations in
the tree any more, so drop these operations and update the code
referring to them accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM: core: Fix device_pm_check_callbacks()

The device_pm_check_callbacks() function doesn't check legacy
->suspend and ->resume callback pointers under the device's
bus type, class and driver, so in some cases it may set the
no_pm_callbacks flag for the device incorrectly and then the
callbacks may be skipped during system suspend/resume, which
shouldn't happen.

Fixes: aa8e54b55947 (PM / sleep: Go direct_complete if driver has no callbacks)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 4.5+ <stable@vger.kernel.org> # 4.5+

PM / sleep: Check pm_wakeup_pending() in __device_suspend_noirq()

Restore the pm_wakeup_pending() check in __device_suspend_noirq()
removed by commit eed4d47efe95 (ACPI / sleep: Ignore spurious SCI
wakeups from suspend-to-idle) as that allows the function to return
earlier if there's a wakeup event pending already (so that it may
spend less time on carrying out operations that will be reversed
shortly anyway) and rework the main suspend-to-idle loop to take
that optimization into account.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Add error argument to dpm_show_time()

Make the core device suspend/resume code also call dpm_show_time()
on failures and add an error argument to this function so that the
message printed by it can reflect the success or failure condition.

This makes the debug messages in question look less confusing in
the failing cases.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / core: Split dpm_suspend_noirq() and dpm_resume_noirq()

Put the device interrupts disabling and enabling as well as
cpuidle_pause() and cpuidle_resume() called during the "noirq"
stages of system suspend into separate functions to allow the
core suspend-to-idle code to be optimized (later).

The only functional difference this makes is that debug facilities
and diagnostic tools will not include the above operations into the
"noirq" device suspend/resume duration measurements.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Do not print debug messages by default

Debug messages from the system suspend/hibernation infrastructure can
fill up the entire kernel log buffer in some cases and anyway they
are only useful for debugging. They depend on CONFIG_PM_DEBUG, but
that is set as a rule as some generally useful diagnostic facilities
depend on it too.

For this reason, avoid printing those messages by default, but make
it possible to turn them on as needed with the help of a new sysfs
attribute under /sys/power/.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: Constify info string used in messages

The 'info' string appearing in many places points to a .rodata string so
it should be passes as pointer to const.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: Constify returned PM event name

The pm_verb() returns a pointer to string from .rodata so it should be
marked as const.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI / PM: Ignore spurious SCI wakeups from suspend-to-idle

The ACPI SCI (System Control Interrupt) is set up as a wakeup IRQ
during suspend-to-idle transitions and, consequently, any events
signaled through it wake up the system from that state. However,
on some systems some of the events signaled via the ACPI SCI while
suspended to idle should not cause the system to wake up. In fact,
quite often they should just be discarded.

Arguably, systems should not resume entirely on such events, but in
order to decide which events really should cause the system to resume
and which are spurious, it is necessary to resume up to the point
when ACPI SCIs are actually handled and processed, which is after
executing dpm_resume_noirq() in the system resume path.

For this reasons, add a loop around freeze_enter() in which the
platforms can process events signaled via multiplexed IRQ lines
like the ACPI SCI and add suspend-to-idle hooks that can be
used for this purpose to struct platform_freeze_ops.

In the ACPI case, the ->wake hook is used for checking if the SCI
has triggered while suspended and deferring the interrupt-induced
system wakeup until the events signaled through it are actually
processed sufficiently to decide whether or not the system should
resume. In turn, the ->sync hook allows all of the relevant event
queues to be flushed so as to prevent events from being missed due
to race conditions.

In addition to that, some ACPI code processing wakeup events needs
to be modified to use the "hard" version of wakeup triggers, so that
it will cause a system resume to happen on device-induced wakeup
events even if the "soft" mechanism to prevent the system from
suspending is not enabled. However, to preserve the existing
behavior with respect to suspend-to-RAM, this only is done in
the suspend-to-idle case and only if an SCI has occurred while
suspended.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Print timing information if debug is enabled

Avoid printing the device suspend/resume timing information if
CONFIG_PM_DEBUG is not set to reduce the log noise level.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Revert "ACPI / sleep: Ignore spurious SCI wakeups from suspend-to-idle"

Revert commit eed4d47efe95 (ACPI / sleep: Ignore spurious SCI wakeups
from suspend-to-idle) as it turned out to be premature and triggered
a number of different issues on various systems.

That includes, but is not limited to, premature suspend-to-RAM aborts
on Dell XPS 13 (9343) reported by Dominik.

The issue the commit in question attempted to address is real and
will need to be taken care of going forward, but evidently more work
is needed for this purpose.

Reported-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI / sleep: Ignore spurious SCI wakeups from suspend-to-idle

The ACPI SCI (System Control Interrupt) is set up as a wakeup IRQ
during suspend-to-idle transitions and, consequently, any events
signaled through it wake up the system from that state. However,
on some systems some of the events signaled via the ACPI SCI while
suspended to idle should not cause the system to wake up. In fact,
quite often they should just be discarded.

Arguably, systems should not resume entirely on such events, but in
order to decide which events really should cause the system to resume
and which are spurious, it is necessary to resume up to the point
when ACPI SCIs are actually handled and processed, which is after
executing dpm_resume_noirq() in the system resume path.

For this reasons, add a loop around freeze_enter() in which the
platforms can process events signaled via multiplexed IRQ lines
like the ACPI SCI and add suspend-to-idle hooks that can be
used for this purpose to struct platform_freeze_ops.

In the ACPI case, the ->wake hook is used for checking if the SCI
has triggered while suspended and deferring the interrupt-induced
system wakeup until the events signaled through it are actually
processed sufficiently to decide whether or not the system should
resume. In turn, the ->sync hook allows all of the relevant event
queues to be flushed so as to prevent events from being missed due
to race conditions.

In addition to that, some ACPI code processing wakeup events needs
to be modified to use the "hard" version of wakeup triggers, so that
it will cause a system resume to happen on device-induced wakeup
events even if the "soft" mechanism to prevent the system from
suspending is not enabled (that also helps to catch device-induced
wakeup events occurring during suspend transitions in progress).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

sched/headers: Prepare for new header dependencies before moving code to <linux/sched/debug.h>

We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/debug.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

ktime: Cleanup ktime_set() usage

ktime_set(S,N) was required for the timespec storage type and is still
useful for situations where a Seconds and Nanoseconds part of a time value
needs to be converted. For anything where the Seconds argument is 0, this
is pointless and can be replaced with a simple assignment.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>

PM / core: Fix bug in the error handling of async suspend

If async_suspend is enabled for parent and child devices, then
PM framework has to ensure that parent's async suspend gets called
only after child's async suspend is done. In case if child's async
suspend fails with error, then parent's async suspend must not be
invoked. The current code uses async_error to ensure this but there
is a problem with it in __device_suspend(). This function notifies
the completion of child's async suspend before updating its error
via async_error variable. As a result, parent's async suspend gets
invoked even though it's child suspend has failed. Fix this bug by
updating the async_error before notifying the child's completion.

Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
[ rjw: Rearranged wthitespace ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: don't suspend parent when async child suspend_{noirq, late} fails

Consider two devices, A and B, where B is a child of A, and B utilizes
asynchronous suspend (it does not matter whether A is sync or async). If
B fails to suspend_noirq() or suspend_late(), or is interrupted by a
wakeup (pm_wakeup_pending()), then it aborts and sets the async_error
variable. However, device A does not (immediately) check the async_error
variable; it may continue to run its own suspend_noirq()/suspend_late()
callback. This is bad.

We can resolve this problem by doing our error and wakeup checking
(particularly, for the async_error flag) after waiting for children to
suspend, instead of before. This also helps align the logic for the noirq and
late suspend cases with the logic in __device_suspend().

It's easy to observe this erroneous behavior by, for example, forcing a
device to sleep a bit in its suspend_noirq() (to ensure the parent is
waiting for the child to complete), then return an error, and watch the
parent suspend_noirq() still get called. (Or similarly, fake a wakeup
event at the right (or is it wrong?) time.)

Fixes: de377b397272 (PM / sleep: Asynchronous threads for suspend_late)
Fixes: 28b6fd6e3779 (PM / sleep: Asynchronous threads for suspend_noirq)
Reported-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Make async suspend/resume of devices use device links

Make the device suspend/resume part of the core system
suspend/resume code use device links to ensure that supplier
and consumer devices will be suspended and resumed in the right
order in case of async suspend/resume.

The idea, roughly, is to use dpm_wait() to wait for all consumers
before a supplier device suspend and to wait for all suppliers
before a consumer device resume.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

driver core: Functional dependencies tracking support

Currently, there is a problem with taking functional dependencies
between devices into account.

What I mean by a "functional dependency" is when the driver of device
B needs device A to be functional and (generally) its driver to be
present in order to work properly. This has certain consequences
for power management (suspend/resume and runtime PM ordering) and
shutdown ordering of these devices. In general, it also implies that
the driver of A needs to be working for B to be probed successfully
and it cannot be unbound from the device before the B's driver.

Support for representing those functional dependencies between
devices is added here to allow the driver core to track them and act
on them in certain cases where applicable.

The argument for doing that in the driver core is that there are
quite a few distinct use cases involving device dependencies, they
are relatively hard to get right in a driver (if one wants to
address all of them properly) and it only gets worse if multiplied
by the number of drivers potentially needing to do it. Morever, at
least one case (asynchronous system suspend/resume) cannot be handled
in a single driver at all, because it requires the driver of A to
wait for B to suspend (during system suspend) and the driver of B to
wait for A to resume (during system resume).

For this reason, represent dependencies between devices as "links",
with the help of struct device_link objects each containing pointers
to the "linked" devices, a list node for each of them, status
information, flags, and an RCU head for synchronization.

Also add two new list heads, representing the lists of links to the
devices that depend on the given one (consumers) and to the devices
depended on by it (suppliers), and a "driver presence status" field
(needed for figuring out initial states of device links) to struct
device.

The entire data structure consisting of all of the lists of link
objects for all devices is protected by a mutex (for link object
addition/removal and for list walks during device driver probing
and removal) and by SRCU (for list walking in other case that will
be introduced by subsequent change sets). If CONFIG_SRCU is not
selected, however, an rwsem is used for protecting the entire data
structure.

In addition, each link object has an internal status field whose
value reflects whether or not drivers are bound to the devices
pointed to by the link or probing/removal of their drivers is in
progress etc. That field is only modified under the device links
mutex, but it may be read outside of it in some cases (introduced by
subsequent change sets), so modifications of it are annotated with
WRITE_ONCE().

New links are added by calling device_link_add() which takes three
arguments: pointers to the devices in question and flags. In
particular, if DL_FLAG_STATELESS is set in the flags, the link status
is not to be taken into account for this link and the driver core
will not manage it. In turn, if DL_FLAG_AUTOREMOVE is set in the
flags, the driver core will remove the link automatically when the
consumer device driver unbinds from it.

One of the actions carried out by device_link_add() is to reorder
the lists used for device shutdown and system suspend/resume to
put the consumer device along with all of its children and all of
its consumers (and so on, recursively) to the ends of those lists
in order to ensure the right ordering between all of the supplier
and consumer devices.

For this reason, it is not possible to create a link between two
devices if the would-be supplier device already depends on the
would-be consumer device as either a direct descendant of it or a
consumer of one of its direct descendants or one of its consumers
and so on.

There are two types of link objects, persistent and non-persistent.
The persistent ones stay around until one of the target devices is
deleted, while the non-persistent ones are removed automatically when
the consumer driver unbinds from its device (ie. they are assumed to
be valid only as long as the consumer device has a driver bound to
it). Persistent links are created by default and non-persistent
links are created when the DL_FLAG_AUTOREMOVE flag is passed
to device_link_add().

Both persistent and non-persistent device links can be deleted
with an explicit call to device_link_del().

Links created without the DL_FLAG_STATELESS flag set are managed
by the driver core using a simple state machine. There are 5 states
each link can be in: DORMANT (unused), AVAILABLE (the supplier driver
is present and functional), CONSUMER_PROBE (the consumer driver is
probing), ACTIVE (both supplier and consumer drivers are present and
functional), and SUPPLIER_UNBIND (the supplier driver is unbinding).
The driver core updates the link state automatically depending on
what happens to the linked devices and for each link state specific
actions are taken in addition to that.

For example, if the supplier driver unbinds from its device, the
driver core will also unbind the drivers of all of its consumers
automatically under the assumption that they cannot function
properly without the supplier. Analogously, the driver core will
only allow the consumer driver to bind to its device if the
supplier driver is present and functional (ie. the link is in
the AVAILABLE state). If that's not the case, it will rely on
the existing deferred probing mechanism to wait for the supplier
driver to become available.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM / sleep: Handle failures in device_suspend_late() consistently

Grygorii Strashko reports:

The PM runtime will be left disabled for the device if its
.suspend_late() callback fails and async suspend is not allowed
for this device. In this case device will not be added in
dpm_late_early_list and dpm_resume_early() will ignore this
device, as result PM runtime will be disabled for it forever
(side effect: after 8 subsequent failures for the same device
the PM runtime will be reenabled due to disable_depth overflow).

To fix this problem, add devices to dpm_late_early_list regardless
of whether or not device_suspend_late() returns errors for them.

That will ensure failures in there to be handled consistently for
all devices regardless of their async suspend/resume status.

Reported-by: Grygorii Strashko <grygorii.strashko@ti.com>
Tested-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: All applicable <stable@vger.kernel.org>

PM / sleep: Drop unused `info' variable

Commit 32e8d689dc12 (PM / sleep: trace_device_pm_callback coverage in
dpm_prepare/complete) removed all users of this variable but forgot to
remove the variable itself.

Signed-off-by: Thierry Reding <treding@nvidia.com>
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Go direct_complete if driver has no callbacks

If a suitable prepare callback cannot be found for a given device and
its driver has no PM callbacks at all, assume that it can go direct to
complete when the system goes to sleep.

The reason for this is that there's lots of devices in a system that do
no PM at all and there's no reason for them to prevent their ancestors
to do direct_complete if they can support it.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: prohibit devices probing during suspend/hibernation

It is unsafe [1] if probing of devices will happen during suspend or
hibernation and system behavior will be unpredictable in this case.
So, let's prohibit device's probing in dpm_prepare() and defer their
probing instead. The normal behavior will be restored in
dpm_complete().

This patch introduces new DD core APIs:
device_block_probing()
It will disable probing of devices and defer their probes instead.
device_unblock_probing()
It will restore normal behavior and trigger re-probing of deferred
devices.

[1] https://lkml.org/lkml/2015/9/11/554

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Allow devices without runtime PM to do direct-complete

Don't unset the direct_complete flag on devices that have runtime PM
disabled, if they are runtime suspended.

This is needed because otherwise ancestor devices wouldn't be able to
do direct_complete without adding runtime PM support to all its
descendants.

Also removes pm_runtime_suspended_if_enabled() because it's now unused.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: trace_device_pm_callback coverage in dpm_prepare/complete

Move the trace_device_pm_callback locations for dpm_prepare and dpm_complete
to encompass the attempt to capture the device mutex prior to callback. This
is needed by analyze_suspend to identify gaps in the trace output caused by
the delay in locking the mutex for a device.

Signed-off-by: Todd Brandt <todd.e.brandt@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / Wakeirq: Add automated device wake IRQ handling

Turns out we can automate the handling for the device_may_wakeup()
quite a bit by using the kernel wakeup source list as suggested
by Rafael J. Wysocki <rjw@rjwysocki.net>.

And as some hardware has separate dedicated wake-up interrupt
in addition to the IO interrupt, we can automate the handling by
adding a generic threaded interrupt handler that just calls the
device PM runtime to wake up the device.

This allows dropping code from device drivers as we currently
are doing it in multiple ways, and often wrong.

For most drivers, we should be able to drop the following
boilerplate code from runtime_suspend and runtime_resume
functions:

...
device_init_wakeup(dev, true);
...
if (device_may_wakeup(dev))
enable_irq_wake(irq);
...
if (device_may_wakeup(dev))
disable_irq_wake(irq);
...
device_init_wakeup(dev, false);
...

We can replace it with just the following init and exit
time code:

...
device_init_wakeup(dev, true);
dev_pm_set_wake_irq(dev, irq);
...
dev_pm_clear_wake_irq(dev);
device_init_wakeup(dev, false);
...

And for hardware with dedicated wake-up interrupts:

...
device_init_wakeup(dev, true);
dev_pm_set_dedicated_wake_irq(dev, irq);
...
dev_pm_clear_wake_irq(dev);
device_init_wakeup(dev, false);
...

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: add pm-trace support for suspending phase

Occasionally, the system can't come back up after suspend/resume
due to problems of device suspending phase. This patch make
PM_TRACE infrastructure cover device suspending phase of
suspend/resume process, and the information in RTC can tell
developers which device suspending function make system hang.

Signed-off-by: Zhonghui Fu <zhonghui.fu@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / Sleep: fix async suspend_late/freeze_late error handling

If an asynchronous suspend_late or freeze_late callback fails
during the SUSPEND, FREEZE or QUIESCE phases, we don't propagate the
corresponding error correctly, in effect ignoring the error and
continuing the suspend-to-ram/hibernation. During suspend-to-ram this
could leave some devices without a valid saved context, leading to a
failure to reinitialize them during resume. During hibernation this
could leave some devices active interfeering with the creation /
restoration of the hibernation image. Also this could leave the
corresponding devices without a valid saved context and failure to
reinitialize them during resume.

Fixes: de377b397272 (PM / sleep: Asynchronous threads for suspend_late)
Signed-off-by: Imre Deak <imre.deak@intel.com>
Cc: 3.15+ <stable@vger.kernel.org> # 3.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Export dpm_suspend_late/noirq() and dpm_resume_early/noirq()

Subsequent change sets will add platform-related operations between
dpm_suspend_late() and dpm_suspend_noirq() as well as between
dpm_resume_noirq() and dpm_resume_early() in suspend_enter(), so
export these functions for suspend_enter() to be able to call them
separately and split the invocations of dpm_suspend_end() and
dpm_resume_start() in there accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: fix kernel-doc warnings in drivers/base/power/main.c

Fix kernel-doc warnings in drivers/base/power/main.c:

Warning(..//drivers/base/power/main.c:473): No description found for parameter 'async'
Warning(..//drivers/base/power/main.c:601): No description found for parameter 'async'
Warning(..//drivers/base/power/main.c:1012): No description found for parameter 'async'
Warning(..//drivers/base/power/main.c:1151): No description found for parameter 'async'
Warning(..//drivers/base/power/main.c:1305): No description found for parameter 'info'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: trace events for device PM callbacks

Adds two trace events which supply the same info that initcall_debug
provides, but via ftrace instead of dmesg. The existing initcall_debug
calls require the pm_print_times_enabled var to be set (either via
sysfs or via the kernel cmd line). The new trace events provide all the
same info as the initcall_debug prints but with less overhead, and also
with coverage of device prepare and complete device callbacks.

These events replace the device_pm_report_time event (which has been
removed). device_pm_callback_start is called first and provides the device
and callback info. device_pm_callback_end is called after with the
device name and error info. The time and pid are gathered from the trace
data headers.

Signed-off-by: Todd Brandt <todd.e.brandt@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: trace events for suspend/resume

Adds trace events that give finer resolution into suspend/resume. These
events are graphed in the timelines generated by the analyze_suspend.py
script. They represent large areas of time consumed that are typical to
suspend and resume.

The event is triggered by calling the function "trace_suspend_resume"
with three arguments: a string (the name of the event to be displayed
in the timeline), an integer (case specific number, such as the power
state or cpu number), and a boolean (where true is used to denote the start
of the timeline event, and false to denote the end).

The suspend_resume trace event reproduces the data that the machine_suspend
trace event did, so the latter has been removed.

Signed-off-by: Todd Brandt <todd.e.brandt@intel.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Mechanism to avoid resuming runtime-suspended devices unnecessarily

Currently, some subsystems (e.g. PCI and the ACPI PM domain) have to
resume all runtime-suspended devices during system suspend, mostly
because those devices may need to be reprogrammed due to different
wakeup settings for system sleep and for runtime PM.

For some devices, though, it's OK to remain in runtime suspend
throughout a complete system suspend/resume cycle (if the device was in
runtime suspend at the start of the cycle). We would like to do this
whenever possible, to avoid the overhead of extra power-up and power-down
events.

However, problems may arise because the device's descendants may require
it to be at full power at various points during the cycle. Therefore the
most straightforward way to do this safely is if the device and all its
descendants can remain runtime suspended until the complete stage of
system resume.

To this end, introduce a new device PM flag, power.direct_complete
and modify the PM core to use that flag as follows.

If the ->prepare() callback of a device returns a positive number,
the PM core will regard that as an indication that it may leave the
device runtime-suspended. It will then check if the system power
transition in progress is a suspend (and not hibernation in particular)
and if the device is, indeed, runtime-suspended. In that case, the PM
core will set the device's power.direct_complete flag. Otherwise it
will clear power.direct_complete for the device and it also will later
clear it for the device's parent (if there's one).

Next, the PM core will not invoke the ->suspend() ->suspend_late(),
->suspend_irq(), ->resume_irq(), ->resume_early(), or ->resume()
callbacks for all devices having power.direct_complete set. It
will invoke their ->complete() callbacks, however, and those
callbacks are then responsible for resuming the devices as
appropriate, if necessary. For example, in some cases they may
need to queue up runtime resume requests for the devices using
pm_request_resume().

Changelog partly based on an Alan Stern's description of the idea
(http://marc.info/?l=linux-pm&m=139940466625569&w=2).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>

cpufreq: suspend governors on system suspend/hibernate

This patch adds cpufreq suspend/resume calls to dpm_{suspend|resume}()
for handling suspend/resume of cpufreq governors.

Lan Tianyu (Intel) & Jinhyuk Choi (Broadcom) found an issue where the
tunables configuration for clusters/sockets with non-boot CPUs was
lost after system suspend/resume, as we were notifying governors with
CPUFREQ_GOV_POLICY_EXIT on removal of the last CPU for that policy
which caused the tunables memory to be freed.

This is fixed by preventing any governor operations from being
carried out between the device suspend and device resume stages of
system suspend and resume, respectively.

We could have added these callbacks at dpm_{suspend|resume}_noirq()
level, but there is an additional problem that the majority of I/O
devices is already suspended at that point and if cpufreq drivers
want to change the frequency before suspending, then that not be
possible on some platforms (which depend on peripherals like i2c,
regulators, etc).

Reported-and-tested-by: Lan Tianyu <tianyu.lan@intel.com>
Reported-by: Jinhyuk Choi <jinchoi@broadcom.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[rjw: Changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Asynchronous threads for suspend_late

In analogy with commits 5af84b82701a and 97df8c12995, using
asynchronous threads can improve the overall suspend_late
time significantly.

This patch is for suspend_late phase.

Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Asynchronous threads for suspend_noirq

In analogy with commits 5af84b82701a and 97df8c12995, using
asynchronous threads can improve the overall suspend_noirq
time significantly.

This patch is for suspend_noirq phase.

Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Asynchronous threads for resume_early

In analogy with commits 5af84b82701a and 97df8c12995, using
asynchronous threads can improve the overall resume_early
time significantly.

This patch is for resume_early phase.

Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Asynchronous threads for resume_noirq

In analogy with commits 5af84b82701a and 97df8c12995, using
asynchronous threads can improve the overall resume_noirq time
significantly.

One typical case is:
In resume_noirq phase and for the PCI devices, the function
pci_pm_resume_noirq() will be called, and there is one d3_delay
(10ms) at least.

With the way of asynchronous threads, we just need wait d3_delay
time once in parallel for each calling, which saves much time to
resume quickly.

Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / sleep: Two flags for async suspend_noirq and suspend_late

The patch is a helper adding two new flags for implementing
async threads for suspend_noirq and suspend_late.

Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Revert "cpufreq: suspend governors on system suspend/hibernate"

Commit 5a87182aa21d (cpufreq: suspend governors on system
suspend/hibernate) causes hibernation problems to happen on
Bjørn Mork's and Paul Bolle's systems, so revert it.

Fixes: 5a87182aa21d (cpufreq: suspend governors on system suspend/hibernate)
Reported-by: Bjørn Mork <bjorn@mork.no>
Reported-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

cpufreq: suspend governors on system suspend/hibernate

This patch adds cpufreq suspend/resume calls to dpm_{suspend|resume}_noirq()
for handling suspend/resume of cpufreq governors.

Lan Tianyu (Intel) & Jinhyuk Choi (Broadcom) found anr issue where
tunables configuration for clusters/sockets with non-boot CPUs was
getting lost after suspend/resume, as we were notifying governors
with CPUFREQ_GOV_POLICY_EXIT on removal of the last cpu for that
policy and so deallocating memory for tunables. This is fixed by
this patch as we don't allow any operation on governors after
device suspend and before device resume now.

Reported-and-tested-by: Lan Tianyu <tianyu.lan@intel.com>
Reported-by: Jinhyuk Choi <jinchoi@broadcom.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[rjw: Changelog, minor cleanups]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

tree-wide: use reinit_completion instead of INIT_COMPLETION

Use this new function to make code more comprehensible, since we are
reinitialzing the completion, not initializing.

[akpm@linux-foundation.org: linux-next resyncs]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13)
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

PM / Runtime: Fix error path for prepare

If a device prepare callback for some reason would fail, the PM core
prevented the device from going inactive forever.

In this case, to reverse the pm_runtime_get_noresume() we invokes the
asyncronous pm_runtime_put(), thus restoring the usage count.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / Sleep: Detect device suspend/resume lockup and log event

Rather than hard-lock the kernel, dump the suspend/resume thread stack
and panic() to capture a message in pstore when a driver takes too long
to suspend/resume. Default suspend/resume watchdog timeout is set to 12
seconds to be longer than the usbhid 10 second timeout, but could be
changed at compile time.

Exclude from the watchdog the time spent waiting for children that
are resumed asynchronously and time every device, whether or not they
resumed synchronously.

This patch is targeted for mobile devices where a suspend/resume lockup
could cause a system reboot. Information about failing device can be
retrieved in subsequent boot session by mounting pstore and inspecting
the log. Laptops with EFI-enabled pstore could also benefit from
this feature.

The hardware watchdog timer is likely suspended during this time and
couldn't be relied upon. The soft-lockup detector would eventually tell
that tasks are not scheduled, but would provide little context as to why.
The patch hence uses system timer and assumes it is still active while the
devices are suspended/resumed.

This feature can be enabled/disabled during kernel configuration.

This change is based on earlier work by San Mehat.

Signed-off-by: Benoit Goby <benoit@android.com>
Signed-off-by: Zoran Markovic <zoran.markovic@linaro.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / Sleep: new trace event to print device suspend and resume times

A new trace event is added to PM events to print the time it takes to
suspend and resume a device. It generates trace messages that
include device, driver, parent information in addition to the type of
PM ops invoked as well as the PM event and error status from the PM
ops. Example trace below:

bash-2239 [000] .... 290.883035: device_pm_report_time: backlight
acpi_video0 parent=0000:00:02.0 state=freeze ops=class nsecs=332 err=0
bash-2239 [000] .... 290.883041: device_pm_report_time: rfkill rf
kill3 parent=phy0 state=freeze ops=legacy class nsecs=216 err=0
bash-2239 [001] .... 290.973892: device_pm_report_time: ieee80211
phy0 parent=0000:01:00.0 state=freeze ops=legacy class nsecs=90846477 err=0

bash-2239 [001] .... 293.660129: device_pm_report_time: ieee80211 phy0 parent=0000:01:00.0 state=restore ops=legacy class nsecs=101295162 err=0
bash-2239 [001] .... 293.660147: device_pm_report_time: rfkill rfkill3 parent=phy0 state=restore ops=legacy class nsecs=1804 err=0
bash-2239 [001] .... 293.660157: device_pm_report_time: backlight acpi_video0 parent=0000:00:02.0 state=restore ops=class nsecs=757 err=0

Signed-off-by: Shuah Khan <shuah.kh@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / Runtime: Asyncronous idle|suspend devices at system resume

Use the asyncronous runtime PM API when returning the runtime
reference for the device after the system resume is completed.

By using the asyncronous runtime PM API we don't have to wait
for each an every device to become idle|suspended. Instead we
can move on and handle the next device in queue.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM / QoS: Remove device PM QoS sysfs attributes at the right place

Device PM QoS sysfs attributes, if present during device removal,
are removed from within device_pm_remove(), which is too late,
since dpm_sysfs_remove() has already removed the whole attribute
group they belonged to. However, moving the removal of those
attributes to dpm_sysfs_remove() alone is not sufficient, because
in theory they still can be re-added right after being removed by it
(the device's driver is still bound to it at that point).

For this reason, move the entire desctruction of device PM QoS
constraints to dpm_sysfs_remove() and make it prevent any new
constraints from being added after it has run. Also, move the
initialization of the power.qos field in struct device to
device_pm_init_common() and drop the no longer needed
dev_pm_qos_constraints_init().

Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

PM: Move disabling/enabling runtime PM to late suspend/early resume

Currently, the PM core disables runtime PM for all devices right
after executing subsystem/driver .suspend() callbacks for them
and re-enables it right before executing subsystem/driver .resume()
callbacks for them. This may lead to problems when there are
two devices such that the .suspend() callback executed for one of
them depends on runtime PM working for the other. In that case,
if runtime PM has already been disabled for the second device,
the first one's .suspend() won't work correctly (and analogously
for resume).

To make those issues go away, make the PM core disable runtime PM
for devices right before executing subsystem/driver .suspend_late()
callbacks for them and enable runtime PM for them right after
executing subsystem/driver .resume_early() callbacks for them. This
way the potential conflitcs between .suspend_late()/.resume_early()
and their runtime PM counterparts are still prevented from happening,
but the subtle ordering issues related to disabling/enabling runtime
PM for devices during system suspend/resume are much easier to avoid.

Reported-and-tested-by: Jan-Matthias Braun <jan_braun@gmx.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Kevin Hilman <khilman@deeprootsystems.com>
Cc: 3.4+ <stable@vger.kernel.org>

PM: Prevent runtime suspend during system resume

This patch (as1591) moves the pm_runtime_get_noresume() and
pm_runtime_put_sync() calls from __device_suspend() and
device_resume() to device_prepare() and device_complete() in the PM
core.

The reason for doing this is to make sure that parent devices remain
at full power (i.e., don't go into runtime suspend) while their
children are being resumed from a system sleep.

The PCI core already contained equivalent code to serve the same
purpose. The patch removes the duplicated code, since it is no longer
needed. One of the comments from the PCI core gets moved into the PM
core, and a second comment is added to explain whe the _get_noresume
and _put_sync calls are present.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: use resume event when call dpm_resume_early

When dpm_suspend_noirq fail, state is PMSG_SUSPEND,
should change to PMSG_RESUME when dpm_resume_early is called

Signed-off-by: Feng Hong <hongfeng@marvell.com>
Signed-off-by: Raul Xiong <xjian@marvell.com>
Signed-off-by: Neil Zhang <zhangwm@marvell.com>
Cc: stable@vger.kernel.org
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Domains: Move syscore flag from subsys data to struct device

The syscore device PM flag is used to mark the devices (belonging to
a PM domain) that should never be turned off, except for the system
core (syscore) suspend/hibernation and resume stages. That flag is
stored in the device's struct pm_subsys_data object whose address is
available from struct device. However, in some situations it may be
convenient to set that flag before the device is added to a PM
domain, so it is better to move it directly to the "power" member of
struct device. Then, it can be checked by the routines in
drivers/base/power/runtime.c and drivers/base/power/main.c, which is
more straightforward.

This also reduces the number of dev_gpd_data() invocations in the
generic PM domains framework, so the overhead related to the syscore
flag is slightly smaller.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Magnus Damm <damm@opensource.se>

PM: Reorganize device PM initialization

Make the device power management initialization more straightforward
by moving the initialization of common (i.e. used by both runtime PM
and system suspend) fields to a separate routine.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: introduce dpm_for_each_dev

dpm_list and its pm lock provide a good way to iterate all
devices in system. Except this way, there is no other easy
way to iterate devices in system.

firmware loader need to cache firmware images for devices
before system sleep, so introduce the function to meet its
demand.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM / Sleep: call early resume handlers when suspend_noirq fails

Commit cf579dfb82550e34de7ccf3ef090d8b834ccd3a9 (PM / Sleep: Introduce
"late suspend" and "early resume" of devices) introduced a bug where
suspend_late handlers would be called, but if dpm_suspend_noirq returned
an error the early_resume handlers would never be called. All devices
would end up on the dpm_late_early_list, and would never be resumed
again.

Fix it by calling dpm_resume_early when dpm_suspend_noirq returns
an error.

Signed-off-by: Colin Cross <ccross@android.com>
Cc: stable@vger.kernel.org
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: Add missing static storage class specifiers in main.c

Fix the following sparse warnings:
drivers/base/power/main.c:48:1: warning: symbol 'dpm_prepared_list' was not declared. Should it be static?
drivers/base/power/main.c:49:1: warning: symbol 'dpm_suspended_list' was not declared. Should it be static?
drivers/base/power/main.c:50:1: warning: symbol 'dpm_late_early_list' was not declared. Should it be static?
drivers/base/power/main.c:51:1: warning: symbol 'dpm_noirq_list' was not declared. Should it be static?

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / cpuidle: System resume hang fix with cpuidle

On certain bios, resume hangs if cpus are allowed to enter idle states
during suspend [1].

This was fixed in apci idle driver [2].But intel_idle driver does not
have this fix. Thus instead of replicating the fix in both the idle
drivers, or in more platform specific idle drivers if needed, the
more general cpuidle infrastructure could handle this.

A suspend callback in cpuidle_driver could handle this fix. But
a cpuidle_driver provides only basic functionalities like platform idle
state detection capability and mechanisms to support entry and exit
into CPU idle states. All other cpuidle functions are found in the
cpuidle generic infrastructure for good reason that all cpuidle
drivers, irrepective of their platforms will support these functions.

One option therefore would be to register a suspend callback in cpuidle
which handles this fix. This could be called through a PM_SUSPEND_PREPARE
notifier. But this is too generic a notfier for a driver to handle.

Also, ideally the job of cpuidle is not to handle side effects of suspend.
It should expose the interfaces which "handle cpuidle 'during' suspend"
or any other operation, which the subsystems call during that respective
operation.

The fix demands that during suspend, no cpus should be allowed to enter
deep C-states. The interface cpuidle_uninstall_idle_handler() in cpuidle
ensures that. Not just that it also kicks all the cpus which are already
in idle out of their idle states which was being done during cpu hotplug
through a CPU_DYING_FROZEN callbacks.

Now the question arises about when during suspend should
cpuidle_uninstall_idle_handler() be called. Since we are dealing with
drivers it seems best to call this function during dpm_suspend().
Delaying the call till dpm_suspend_noirq() does no harm, as long as it is
before cpu_hotplug_begin() to avoid race conditions with cpu hotpulg
operations. In dpm_suspend_noirq(), it would be wise to place this call
before suspend_device_irqs() to avoid ugly interactions with the same.

Ananlogously, during resume.

References:
[1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/674075.
[2] http://marc.info/?l=linux-pm&m=133958534231884&w=2

Reported-and-tested-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: Separate printing suspend times from initcall_debug

Change the behavior of the newly introduced
/sys/power/pm_print_times attribute so that its initial value
depends on initcall_debug, but setting it to 0 will cause device
suspend/resume times not to be printed, even if initcall_debug has
been set. This way, the people who use initcall_debug for reasons
other than PM debugging will be able to switch the suspend/resume
times printing off, if need be.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM / Sleep: add knob for printing device resume times

Added a new knob called /sys/power/pm_print_times. Setting it to 1
enables printing of time taken by devices to suspend and resume.
Setting it to 0 disables this printing (unless overridden by
initcall_debug kernel command line option).

Signed-off-by: Sameer Nanda <snanda@chromium.org>
Acked-by: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: Prevent waiting forever on asynchronous suspend after abort

__device_suspend() must always send a completion. Otherwise, parent
devices will wait forever.

Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and
system sleep (v2)", introduced a regression by short-circuiting the
complete_all() for certain error cases.

This patch fixes the bug by always signalling a completion.

Addresses http://crosbug.com/31972

Tested by injecting an abort.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: Look for wakeup events in later stages of device suspend

Currently, the device suspend code in drivers/base/power/main.c
only checks if there have been any wakeup events, and therefore the
ongoing system transition to a sleep state should be aborted, during
the first (i.e. "suspend") device suspend phase. However, wakeup
events may be reported later as well, so it's reasonable to look for
them in the in the subsequent (i.e. "late suspend" and "suspend
noirq") phases.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PM / Sleep: Introduce "late suspend" and "early resume" of devices

The current device suspend/resume phases during system-wide power
transitions appear to be insufficient for some platforms that want
to use the same callback routines for saving device states and
related operations during runtime suspend/resume as well as during
system suspend/resume. In principle, they could point their
.suspend_noirq() and .resume_noirq() to the same callback routines
as their .runtime_suspend() and .runtime_resume(), respectively,
but at least some of them require device interrupts to be enabled
while the code in those routines is running.

It also makes sense to have device suspend-resume callbacks that will
be executed with runtime PM disabled and with device interrupts
enabled in case someone needs to run some special code in that
context during system-wide power transitions.

Apart from this, .suspend_noirq() and .resume_noirq() were introduced
as a workaround for drivers using shared interrupts and failing to
prevent their interrupt handlers from accessing suspended hardware.
It appears to be better not to use them for other porposes, or we may
have to deal with some serious confusion (which seems to be happening
already).

For the above reasons, introduce new device suspend/resume phases,
"late suspend" and "early resume" (and analogously for hibernation)
whose callback will be executed with runtime PM disabled and with
device interrupts enabled and whose callback pointers generally may
point to runtime suspend/resume routines.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>

PM: Run the driver callback directly if the subsystem one is not there

Make the PM core execute driver PM callbacks directly if the
corresponding subsystem callbacks are not present.

There are three reasons for doing that. First, it reflects the
behavior of drivers/base/dd.c:really_probe() that runs the driver's
.probe() callback directly if the bus type's one is not defined, so
this change will remove one arbitrary difference between the PM core
and the remaining parts of the driver core. Second, it will allow
some subsystems, whose PM callbacks don't do anything except for
executing driver callbacks, to be simplified quite a bit by removing
those "forward-only" callbacks. Finally, it will allow us to remove
one level of indirection in the system suspend and resume code paths
where it is not necessary, which is going to lead to less debug noise
with initcall_debug passed in the kernel command line (messages won't
be printed for driverless devices whose subsystems don't provide
PM callbacks among other things).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: Make pm_op() and pm_noirq_op() return callback pointers

Make the pm_op() and pm_noirq_op() functions return pointers to
appropriate callbacks instead of executing those callbacks and
returning their results.

This change is required for a subsequent modification that will
execute the corresponding driver callback if the subsystem
callback returned by either pm_op(), or pm_noirq_op() is NULL.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Sleep: Unify diagnostic messages from device suspend/resume

Make pm_op() and pm_noirq_op() use the same helper function for
running callbacks, which will cause them to use the same format of
diagnostic messages. This also reduces the complexity and size of
the code quite a bit.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

PM / Sleep: Simplify device_suspend_noirq()

Remove a few if () and return statements in device_suspend_noirq()
that aren't really necessary.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>

PM / Sleep: Remove unnecessary label and jumps to it form PM core code

The "End" label in device_prepare() in drivers/base/power/main.c is
not necessary and the jumps to it have no real effect, so remove them
all.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>

PM Sleep: Do not extend wakeup paths to devices with ignore_children set

Commit 4ca46ff3e0d8c234cb40ebb6457653b59584426c (PM / Sleep: Mark
devices involved in wakeup signaling during suspend) introduced
the power.wakeup_path field in struct dev_pm_info to mark devices
whose children are enabled to wake up the system from sleep states,
so that power domains containing the parents that provide their
children with wakeup power and/or relay their wakeup signals are not
turned off. Unfortunately, that introduced a PM regression on SH7372
whose power consumption in the system "memory sleep" state increased
as a result of it, because it prevented the power domain containing
the I2C controller from being turned off when some children of that
controller were enabled to wake up the system, although the
controller was not necessary for them to signal wakeup.

To fix this issue use the observation that devices whose
power.ignore_children flag is set for runtime PM should be treated
analogously during system suspend. Namely, they shouldn't be
included in wakeup paths going through their children. Since the
SH7372 I2C controller's power.ignore_children flag is set, doing so
will restore the previous behavior of that SOC.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/base: Add export.h for EXPORT_SYMBOL/THIS_MODULE as required.

Most of these files were implicitly getting EXPORT_SYMBOL via
device.h which was including module.h, but that path will be broken
soon.

[ with input from Stephen Rothwell <sfr@canb.auug.org.au> ]

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

PM / Sleep: Mark devices involved in wakeup signaling during suspend

The generic PM domains code in drivers/base/power/domain.c has
to avoid powering off domains that provide power to wakeup devices
during system suspend. Currently, however, this only works for
wakeup devices directly belonging to the given domain and not for
their children (or the children of their children and so on).
Thus, if there's a wakeup device whose parent belongs to a power
domain handled by the generic PM domains code, the domain will be
powered off during system suspend preventing the device from
signaling wakeup.

To address this problem introduce a device flag, power.wakeup_path,
that will be set during system suspend for all wakeup devices,
their parents, the parents of their parents and so on. This way,
all wakeup paths in the device hierarchy will be marked and the
generic PM domains code will only need to avoid powering off
domains containing devices whose power.wakeup_path is set.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Suspend: Add statistics debugfs file for suspend to RAM

Record S3 failure time about each reason and the latest two failed
devices' names in S3 progress.
We can check it through 'suspend_stats' entry in debugfs.

The motivation of the patch:

We are enabling power features on Medfield. Comparing with PC/notebook,
a mobile enters/exits suspend-2-ram (we call it s3 on Medfield) far
more frequently. If it can't enter suspend-2-ram in time, the power
might be used up soon.

We often find sometimes, a device suspend fails. Then, system retries
s3 over and over again. As display is off, testers and developers
don't know what happens.

Some testers and developers complain they don't know if system
tries suspend-2-ram, and what device fails to suspend. They need
such info for a quick check. The patch adds suspend_stats under
debugfs for users to check suspend to RAM statistics quickly.

If not using this patch, we have other methods to get info about
what device fails. One is to turn on CONFIG_PM_DEBUG, but users
would get too much info and testers need recompile the system.

In addition, dynamic debug is another good tool to dump debug info.
But it still doesn't match our utilization scenario closely.
1) user need write a user space parser to process the syslog output;
2) Our testing scenario is we leave the mobile for at least hours.
Then, check its status. No serial console available during the
testing. One is because console would be suspended, and the other
is serial console connecting with spi or HSU devices would consume
power. These devices are powered off at suspend-2-ram.

Signed-off-by: ShuoX Liu <shuox.liu@intel.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / QoS: Add function dev_pm_qos_read_value() (v3)

To read the current PM QoS value for a given device we need to
make sure that the device's power.constraints object won't be
removed while we're doing that. For this reason, put the
operation under dev->power.lock and acquire the lock
around the initialization and removal of power.constraints.

Moreover, since we're using the value of power.constraints to
determine whether or not the object is present, the
power.constraints_state field isn't necessary any more and may be
removed. However, dev_pm_qos_add_request() needs to check if the
device is being removed from the system before allocating a new
PM QoS constraints object for it, so make it use the
power.power_state field of struct device for this purpose.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM QoS: Implement per-device PM QoS constraints

Implement the per-device PM QoS constraints by creating a device
PM QoS API, which calls the PM QoS constraints management core code.

The per-device latency constraints data strctures are stored
in the device dev_pm_info struct.

The device PM code calls the init and destroy of the per-device constraints
data struct in order to support the dynamic insertion and removal of the
devices in the system.

To minimize the data usage by the per-device constraints, the data struct
is only allocated at the first call to dev_pm_qos_add_request.
The data is later free'd when the device is removed from the system.
A global mutex protects the constraints users from the data being
allocated and free'd.

Signed-off-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Limit race conditions between runtime PM and system sleep (v2)

One of the roles of the PM core is to prevent different PM callbacks
executed for the same device object from racing with each other.
Unfortunately, after commit e8665002477f0278f84f898145b1f141ba26ee26
(PM: Allow pm_runtime_suspend() to succeed during system suspend)
runtime PM callbacks may be executed concurrently with system
suspend/resume callbacks for the same device.

The main reason for commit e8665002477f0278f84f898145b1f141ba26ee26
was that some subsystems and device drivers wanted to use runtime PM
helpers, pm_runtime_suspend() and pm_runtime_put_sync() in
particular, for carrying out the suspend of devices in their
.suspend() callbacks. However, as it's been determined recently,
there are multiple reasons not to do so, inlcuding:

* The caller really doesn't control the runtime PM usage counters,
because user space can access them through sysfs and effectively
block runtime PM. That means using pm_runtime_suspend() or
pm_runtime_get_sync() to suspend devices during system suspend
may or may not work.

* If a driver calls pm_runtime_suspend() from its .suspend()
callback, it causes the subsystem's .runtime_suspend() callback to
be executed, which leads to the call sequence:

subsys->suspend(dev)
driver->suspend(dev)
pm_runtime_suspend(dev)
subsys->runtime_suspend(dev)

recursive from the subsystem's point of view. For some subsystems
that may actually work (e.g. the platform bus type), but for some
it will fail in a rather spectacular fashion (e.g. PCI). In each
case it means a layering violation.

* Both the subsystem and the driver can provide .suspend_noirq()
callbacks for system suspend that can do whatever the
.runtime_suspend() callbacks do just fine, so it really isn't
necessary to call pm_runtime_suspend() during system suspend.

* The runtime PM's handling of wakeup devices is usually different
from the system suspend's one, so .runtime_suspend() may simply be
inappropriate for system suspend.

* System suspend is supposed to work even if CONFIG_PM_RUNTIME is
unset.

* The runtime PM workqueue is frozen before system suspend, so if
whatever the driver is going to do during system suspend depends
on it, that simply won't work.

Still, there is a good reason to allow pm_runtime_resume() to
succeed during system suspend and resume (for instance, some
subsystems and device drivers may legitimately use it to ensure that
their devices are in full-power states before suspending them).
Moreover, there is no reason to prevent runtime PM callbacks from
being executed in parallel with the system suspend/resume .prepare()
and .complete() callbacks and the code removed by commit
e8665002477f0278f84f898145b1f141ba26ee26 went too far in this
respect. On the other hand, runtime PM callbacks, including
.runtime_resume(), must not be executed during system suspend's
"late" stage of suspending devices and during system resume's "early"
device resume stage.

Taking all of the above into consideration, make the PM core
acquire a runtime PM reference to every device and resume it if
there's a runtime PM resume request pending right before executing
the subsystem-level .suspend() callback for it. Make the PM core
drop references to all devices right after executing the
subsystem-level .resume() callbacks for them. Additionally,
make the PM core disable the runtime PM framework for all devices
during system suspend, after executing the subsystem-level .suspend()
callbacks for them, and enable the runtime PM framework for all
devices during system resume, right before executing the
subsystem-level .resume() callbacks for them.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Kevin Hilman <khilman@ti.com>

PM / Domains: Rename struct dev_power_domain to struct dev_pm_domain

The naming convention used by commit 7538e3db6e015e890825fbd9f86599b
(PM: Add support for device power domains), which introduced the
struct dev_power_domain type for representing device power domains,
evidently confuses some developers who tend to think that objects
of this type must correspond to "power domains" as defined by
hardware, which is not the case. Namely, at the kernel level, a
struct dev_power_domain object can represent arbitrary set of devices
that are mutually dependent power management-wise and need not belong
to one hardware power domain. To avoid that confusion, rename struct
dev_power_domain to struct dev_pm_domain and rename the related
pointers in struct device and struct pm_clk_notifier_block from
pwr_domain to pm_domain.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Kevin Hilman <khilman@ti.com>

PM: Fix async resume following suspend failure

The PM core doesn't handle suspend failures correctly when it comes to
asynchronously suspended devices. These devices are moved onto the
dpm_suspended_list as soon as the corresponding async thread is
started up, and they remain on the list even if they fail to suspend
or the sleep transition is cancelled before they get suspended. As a
result, when the PM core unwinds the transition, it tries to resume
the devices even though they were never suspended.

This patch (as1474) fixes the problem by adding a new "is_suspended"
flag to dev_pm_info. Devices are resumed only if the flag is set.

[rjw:
* Moved the dev->power.is_suspended check into device_resume(),
because we need to complete dev->power.completion and clear
dev->power.is_prepared too for devices whose
dev->power.is_suspended flags are unset.
* Fixed __device_suspend() to avoid setting dev->power.is_suspended
if async_error is different from zero.]

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org

PM: Rename dev_pm_info.in_suspend to is_prepared

This patch (as1473) renames the "in_suspend" field in struct
dev_pm_info to "is_prepared", in preparation for an upcoming change.
The new name is more descriptive of what the field really means.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org

PM: Allow drivers to allocate memory from .prepare() callbacks safely

If device drivers allocate substantial amounts of memory (above 1 MB)
in their hibernate .freeze() callbacks (or in their legacy suspend
callbcks during hibernation), the subsequent creation of hibernate
image may fail due to the lack of memory. This is the case, because
the drivers' .freeze() callbacks are executed after the hibernate
memory preallocation has been carried out and the preallocated amount
of memory may be too small to cover the new driver allocations.
Unfortunately, the drivers' .prepare() callbacks also are executed
after the hibernate memory preallocation has completed, so they are
not suitable for allocating additional memory either. Thus the only
way a driver can safely allocate memory during hibernation is to use
a hibernate/suspend notifier. However, the notifiers are called
before the freezing of user space and the drivers wanting to use them
for allocating additional memory may not know how much memory needs
to be allocated at that point.

To let device drivers overcome this difficulty rework the hibernation
sequence so that the memory preallocation is carried out after the
drivers' .prepare() callbacks have been executed, so that the
.prepare() callbacks can be used for allocating additional memory
to be used by the drivers' .freeze() callbacks. Update documentation
to match the new behavior of the code.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Make power domain callbacks take precedence over subsystem ones

Change the PM core's behavior related to power domains in such a way
that, if a power domain is defined for a given device, its callbacks
will be executed instead of and not in addition to the device
subsystem's PM callbacks.

The idea behind the initial implementation of power domains handling
by the PM core was that power domain callbacks would be executed in
addition to subsystem callbacks, so that it would be possible to
extend the subsystem callbacks by using power domains. It turns out,
however, that this wouldn't be really convenient in some important
situations.

For example, there are systems in which power can only be removed
from entire power domains. On those systems it is not desirable to
execute device drivers' PM callbacks until it is known that power is
going to be removed from the devices in question, which means that
they should be executed by power domain callbacks rather then by
subsystem (e.g. bus type) PM callbacks, because subsystems generally
have no information about what devices belong to which power domain.
Thus, for instance, if the bus type in question is the platform bus
type, its PM callbacks generally should not be called in addition to
power domain callbacks, because they run device drivers' callbacks
unconditionally if defined.

While in principle the default subsystem PM callbacks, or a subset of
them, may be replaced with different functions, it doesn't seem
correct to do so, because that would change the subsystem's behavior
with respect to all devices in the system, regardless of whether or
not they belong to any power domains. Thus, the only remaining
option is to make power domain callbacks take precedence over
subsystem callbacks.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Kevin Hilman <khilman@ti.com>

PM / Wakeup: Fix initialization of wakeup-related device sysfs files

It turns out that some PCI devices are only found to be
wakeup-capable during registration, in which case, when
device_set_wakeup_capable() is called, device_is_registered() already
returns 'true' for the given device, but dpm_sysfs_add() hasn't been
called for it yet. This leads to situations in which the device's
power.can_wakeup flag is not set as requested because of failing
wakeup_sysfs_add() and its wakeup-related sysfs files are not
created, although they should be present. This is a post-2.6.38
regression introduced by commit cb8f51bdadb7969139c2e39c2defd4cde98c1
(PM: Do not create wakeup sysfs files for devices that cannot wake
up).

To work around this problem initialize the device's power.entry
field to an empty list head and make device_set_wakeup_capable()
check if it is still empty before attempting to add the devices
wakeup-related sysfs files with wakeup_sysfs_add(). Namely, if
power.entry is still empty at this point, device_pm_add() hasn't been
called yet for the device and its wakeup-related files will be
created later, so device_set_wakeup_capable() doesn't have to create
them.

Reported-and-tested-by: Tino Keitel <tino.keitel@tikei.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

PM / Hibernate: Introduce CONFIG_HIBERNATE_CALLBACKS

Xen save/restore is going to use hibernate device callbacks for
quiescing devices and putting them back to normal operations and it
would need to select CONFIG_HIBERNATION for this purpose. However,
that also would cause the hibernate interfaces for user space to be
enabled, which might confuse user space, because the Xen kernels
don't support hibernation. Moreover, it would be wasteful, as it
would make the Xen kernels include a substantial amount of code that
they would never use.

To address this issue introduce new power management Kconfig option
CONFIG_HIBERNATE_CALLBACKS, such that it will only select the code
that is necessary for the hibernate device callbacks to work and make
CONFIG_HIBERNATION select it. Then, Xen save/restore will be able to
select CONFIG_HIBERNATE_CALLBACKS without dragging the entire
hibernate code along with it.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Tested-by: Shriram Rajagopalan <rshriram@cs.ubc.ca>

PM: Make system-wide PM and runtime PM treat subsystems consistently

The code handling system-wide power transitions (eg. suspend-to-RAM)
can in theory execute callbacks provided by the device's bus type,
device type and class in each phase of the power transition. In
turn, the runtime PM core code only calls one of those callbacks at
a time, preferring bus type callbacks to device type or class
callbacks and device type callbacks to class callbacks.

It seems reasonable to make them both behave in the same way in that
respect. Moreover, even though a device may belong to two subsystems
(eg. bus type and device class) simultaneously, in practice power
management callbacks for system-wide power transitions are always
provided by only one of them (ie. if the bus type callbacks are
defined, the device class ones are not and vice versa). Thus it is
possible to modify the code handling system-wide power transitions
so that it follows the core runtime PM code (ie. treats the
subsystem callbacks as mutually exclusive).

On the other hand, the core runtime PM code will choose to execute,
for example, a runtime suspend callback provided by the device type
even if the bus type's struct dev_pm_ops object exists, but the
runtime_suspend pointer in it happens to be NULL. This is confusing,
because it may lead to the execution of callbacks from different
subsystems during different operations (eg. the bus type suspend
callback may be executed during runtime suspend of the device, while
the device type callback will be executed during system suspend).

Make all of the power management code treat subsystem callbacks in
a consistent way, such that:
(1) If the device's type is defined (eg. dev->type is not NULL)
and its pm pointer is not NULL, the callbacks from dev->type->pm
will be used.
(2) If dev->type is NULL or dev->type->pm is NULL, but the device's
class is defined (eg. dev->class is not NULL) and its pm pointer
is not NULL, the callbacks from dev->class->pm will be used.
(3) If dev->type is NULL or dev->type->pm is NULL and dev->class is
NULL or dev->class->pm is NULL, the callbacks from dev->bus->pm
will be used provided that both dev->bus and dev->bus->pm are
not NULL.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Kevin Hilman <khilman@ti.com>
Reasoning-sounds-sane-to: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: Add support for device power domains

The platform bus type is often used to handle Systems-on-a-Chip (SoC)
where all devices are represented by objects of type struct
platform_device. In those cases the same "platform" device driver
may be used with multiple different system configurations, but the
actions needed to put the devices it handles into a low-power state
and back into the full-power state may depend on the design of the
given SoC. The driver, however, cannot possibly include all the
information necessary for the power management of its device on all
the systems it is used with. Moreover, the device hierarchy in its
current form also is not suitable for representing this kind of
information.

The patch below attempts to address this problem by introducing
objects of type struct dev_power_domain that can be used for
representing power domains within a SoC. Every struct
dev_power_domain object provides a sets of device power
management callbacks that can be used to perform what's needed for
device power management in addition to the operations carried out by
the device's driver and subsystem.

Namely, if a struct dev_power_domain object is pointed to by the
pwr_domain field in a struct device, the callbacks provided by its
ops member will be executed in addition to the corresponding
callbacks provided by the device's subsystem and driver during all
power transitions.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Tested-and-acked-by: Kevin Hilman <khilman@ti.com>

PM: Allow pm_runtime_suspend() to succeed during system suspend

The dpm_prepare() function increments the runtime PM reference
counters of all devices to prevent pm_runtime_suspend() from
executing subsystem-level callbacks. However, this was supposed to
guard against a specific race condition that cannot happen, because
the power management workqueue is freezable, so pm_runtime_suspend()
can only be called synchronously during system suspend and we can
rely on subsystems and device drivers to avoid doing that
unnecessarily.

Make dpm_prepare() drop the runtime PM reference to each device
after making sure that runtime resume is not pending for it.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Kevin Hilman <khilman@ti.com>

PM: Use dev_name() in core device suspend and resume routines

Use dev_name() wherever applicable in drivers/base/power/main.c.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Permit registration of parentless devices during system suspend

The registration of a new parentless device during system suspend
will not lead to any complications affecting the PM core (the device
will be effectively seen after the subsequent resume has completed),
so remove the code used for detection of such events.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Replace the device power.status field with a bit field

The device power.status field is too complicated for its purpose
(storing the information about whether or not the device is in the
"active" state from the PM core's point of view), so replace it with
a bit field and modify all of its users accordingly.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Remove redundant checks from core device resume routines

Since a separate list of devices is used to link devices that have
completed each stage of suspend (or resume), it is not necessary to
check dev->power.status in the core device resume routines any more.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Use a different list of devices for each stage of device suspend

Instead of keeping all devices in the same list during system suspend
and resume, regardless of what suspend-resume callbacks have been
executed for them already, use separate lists of devices that have
had their ->prepare(), ->suspend() and ->suspend_noirq() callbacks
executed. This will allow us to simplify the core device suspend and
resume routines.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Avoid compiler warning in pm_noirq_op()

The compiler complains that calltime may be uninitialized in
pm_noirq_op(), so add extra initialization for that variable to
avoid the warning.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Use pm_wakeup_pending() in __device_suspend()

Before starting to suspend a device in __device_suspend() check if
there's a request to abort the power transition and return -EBUSY
in that case.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM / Wakeup: Replace pm_check_wakeup_events() with pm_wakeup_pending()

To avoid confusion with the meaning and return value of
pm_check_wakeup_events() replace it with pm_wakeup_pending() that
will work the other way around (ie. return true when system-wide
power transition should be aborted).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Prevent dpm_prepare() from returning errors unnecessarily

Currently dpm_prepare() returns error code if it finds that a device
being suspended has a pending runtime resume request. However, it
should not do that if the checking for wakeup events is not enabled.
On the other hand, if the checking for wakeup events is enabled, it
can return error when a wakeup event is detected, regardless of its
source.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Allow devices to be removed during late suspend and early resume

Holding dpm_list_mtx across late suspend and early resume of devices
is problematic for the PCMCIA subsystem and doesn't allow device
objects to be removed by late suspend and early resume driver
callbacks. This appears to be overly restrictive, as drivers are
generally allowed to remove device objects in other phases of suspend
and resume. Therefore rework dpm_{suspend|resume}_noirq() so that
they don't have to hold dpm_list_mtx all the time.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

tree-wide: fix comment/printk typos

"gadget", "through", "command", "maintain", "maintain", "controller", "address",
"between", "initiali[zs]e", "instead", "function", "select", "already",
"equal", "access", "management", "hierarchy", "registration", "interest",
"relative", "memory", "offset", "already",

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

PM: Fix potential issue with failing asynchronous suspend

There is a potential issue with the asynchronous suspend code that
a device driver suspending asynchronously may not notice that it
should back off. There are two failing scenarions, (1) when the
driver is waiting for a driver suspending synchronously to complete
and that second driver returns error code, in which case async_error
won't be set and the waiting driver will continue suspending and (2)
after the driver has called device_pm_wait_for_dev() and the waited
for driver returns error code, in which case the caller of
device_pm_wait_for_dev() will not know that there was an error and
will continue suspending.

To fix this issue make __device_suspend() set async_error, so
async_suspend() doesn't need to set it any more, and make
device_pm_wait_for_dev() return async_error, so that its callers
can check whether or not they should continue suspending.

No more changes are necessary, since device_pm_wait_for_dev() is
not used by any drivers' suspend routines.

Reported-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

PM / Wakeup: Introduce wakeup source objects and event statistics (v3)

Introduce struct wakeup_source for representing system wakeup sources
within the kernel and for collecting statistics related to them.
Make the recently introduced helper functions pm_wakeup_event(),
pm_stay_awake() and pm_relax() use struct wakeup_source objects
internally, so that wakeup statistics associated with wakeup devices
can be collected and reported in a consistent way (the definition of
pm_relax() is changed, which is harmless, because this function is
not called directly by anyone yet). Introduce new wakeup-related
sysfs device attributes in /sys/devices/.../power for reporting the
device wakeup statistics.

Change the global wakeup events counters event_count and
events_in_progress into atomic variables, so that it is not necessary
to acquire a global spinlock in pm_wakeup_event(), pm_stay_awake()
and pm_relax(), which should allow us to avoid lock contention in
these functions on SMP systems with many wakeup devices.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: Fix signed/unsigned warning in dpm_show_time()

Seen on MIPS32, gcc 4.4.3, 2.6.36-rc4:

drivers/base/power/main.c: In function 'dpm_show_time':
drivers/base/power/main.c:415: warning: comparison of distinct pointer types lacks a cast

do_div() takes unsigned parameters:

uint32_t do_div(uint64_t *n, uint32_t base);

Using an unsigned variable for usecs64 should not cause any problems,
because calltime >= starttime .

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Prevent waiting forever on asynchronous resume after failing suspend

During suspend, the power.completion is expected to be set when a
device has not yet started suspending. Set it on init to fix a
corner case where a device is resumed when its parent has never
suspended.

Consider three drivers, A, B, and C. The parent of A is C, and C
has async_suspend set. On boot, C->power.completion is initialized
to 0.

During the first suspend:
suspend_devices_and_enter(...)
dpm_resume(...)
device_suspend(A)
device_suspend(B) returns error, aborts suspend
dpm_resume_end(...)
dpm_resume(...)
device_resume(A)
dpm_wait(A->parent == C)
wait_for_completion(C->power.completion)

The wait_for_completion will never complete, because
complete_all(C->power.completion) will only be called from
device_suspend(C) or device_resume(C), neither of which is called
if suspend is aborted before C.

After a successful suspend->resume cycle, where B doesn't abort
suspend, C->power.completion is left in the completed state by the
call to device_resume(C), and the same call path will work if B
aborts suspend.

Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Make it possible to avoid races between wakeup and system sleep

One of the arguments during the suspend blockers discussion was that
the mainline kernel didn't contain any mechanisms making it possible
to avoid races between wakeup and system suspend.

Generally, there are two problems in that area. First, if a wakeup
event occurs exactly when /sys/power/state is being written to, it
may be delivered to user space right before the freezer kicks in, so
the user space consumer of the event may not be able to process it
before the system is suspended. Second, if a wakeup event occurs
after user space has been frozen, it is not generally guaranteed that
the ongoing transition of the system into a sleep state will be
aborted.

To address these issues introduce a new global sysfs attribute,
/sys/power/wakeup_count, associated with a running counter of wakeup
events and three helper functions, pm_stay_awake(), pm_relax(), and
pm_wakeup_event(), that may be used by kernel subsystems to control
the behavior of this attribute and to request the PM core to abort
system transitions into a sleep state already in progress.

The /sys/power/wakeup_count file may be read from or written to by
user space. Reads will always succeed (unless interrupted by a
signal) and return the current value of the wakeup events counter.
Writes, however, will only succeed if the written number is equal to
the current value of the wakeup events counter. If a write is
successful, it will cause the kernel to save the current value of the
wakeup events counter and to abort the subsequent system transition
into a sleep state if any wakeup events are reported after the write
has returned.

[The assumption is that before writing to /sys/power/state user space
will first read from /sys/power/wakeup_count. Next, user space
consumers of wakeup events will have a chance to acknowledge or
veto the upcoming system transition to a sleep state. Finally, if
the transition is allowed to proceed, /sys/power/wakeup_count will
be written to and if that succeeds, /sys/power/state will be written
to as well. Still, if any wakeup events are reported to the PM core
by kernel subsystems after that point, the transition will be
aborted.]

Additionally, put a wakeup events counter into struct dev_pm_info and
make these per-device wakeup event counters available via sysfs,
so that it's possible to check the activity of various wakeup event
sources within the kernel.

To illustrate how subsystems can use pm_wakeup_event(), make the
low-level PCI runtime PM wakeup-handling code use it.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: markgross <markgross@thegnar.org>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>

power: support _noirq actions on device types and classes

The new-style dev_pm_ops provide callbacks for both IRQs enabled
and disabled. However, the _noirq variants were only called for
buses registered with a device, not for classes and types.

In order to properly use dev_pm_ops in class pcmcia_socket_class,
support _noirq actions also on classes and types.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>

Driver core: create lock/unlock functions for struct device

In the future, we are going to be changing the lock type for struct
device (once we get the lockdep infrastructure properly worked out) To
make that changeover easier, and to possibly burry the lock in a
different part of struct device, let's create some functions to lock and
unlock a device so that no out-of-core code needs to be changed in the
future.

This patch creates the device_lock/unlock/trylock() functions, and
converts all in-tree users to them.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Dave Young <hidave.darkstar@gmail.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Phil Carmody <ext-phil.2.carmody@nokia.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Len Brown <len.brown@intel.com>
Cc: Magnus Damm <damm@igel.co.jp>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Alex Chiang <achiang@hp.com>
Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrew Patterson <andrew.patterson@hp.com>
Cc: Yu Zhao <yu.zhao@intel.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Wolfram Sang <w.sang@pengutronix.de>
Cc: CHENG Renquan <rqcheng@smu.edu.sg>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: Frans Pop <elendil@planet.nl>
Cc: David Vrabel <david.vrabel@csr.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: Allow device drivers to use dpm_wait()

There are some dependencies between devices (in particular, between
EHCI USB controllers and their OHCI/UHCI siblings) which are not
reflected by the structure of the device tree. With synchronous
suspend and resume these dependencies are taken into accout
automatically, because the devices in question are always registered
in the right order, but to meet these constraints with asynchronous
suspend and resume the drivers of these devices will need to use
dpm_wait() in their suspend/resume routines, so introduce a helper
function allowing them to do that.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Start asynchronous resume threads upfront

It has been shown by testing that total device resume time can be
reduced significantly (by as much as 50% or more) if the async
threads executing some devices' resume routines are all started
before the main resume thread starts to handle the "synchronous"
devices.

This is a consequence of the fact that the slowest devices tend to be
located at the end of dpm_list, so their resume routines are started
very late. Consequently, they have to wait for all the preceding
"synchronous" devices before their resume routines can be started
by the main resume thread, even if they are "asynchronous". By
starting their async threads upfront we effectively move those
devices towards the beginning of dpm_list, without breaking their
ordering with respect to their parents and children. As a result,
their resume routines are started much earlier and we are able to
save much more device resume time this way.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Add a switch for disabling/enabling asynchronous suspend/resume

Add sysfs attribute /sys/power/pm_async allowing the user space to
disable/enable asynchronous suspend/resume of devices.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Asynchronous suspend and resume of devices

Theoretically, the total time of system sleep transitions (suspend
to RAM, hibernation) can be reduced by running suspend and resume
callbacks of device drivers in parallel with each other. However,
there are dependencies between devices such that we're not allowed
to suspend the parent of a device before suspending the device
itself. Analogously, we're not allowed to resume a device before
resuming its parent.

The most straightforward way to take these dependencies into accout
is to start the async threads used for suspending and resuming
devices at the core level, so that async_schedule() is called for
each suspend and resume callback supposed to be executed
asynchronously.

For this purpose, introduce a new device flag, power.async_suspend,
used to mark the devices whose suspend and resume callbacks are to be
executed asynchronously (ie. in parallel with the main suspend/resume
thread and possibly in parallel with each other) and helper function
device_enable_async_suspend() allowing one to set power.async_suspend
for given device (power.async_suspend is unset by default for all
devices). For each device with the power.async_suspend flag set the
PM core will use async_schedule() to execute its suspend and resume
callbacks.

The async threads started for different devices as a result of
calling async_schedule() are synchronized with each other and with
the main suspend/resume thread with the help of completions, in the
following way:
(1) There is a completion, power.completion, for each device object.
(2) Each device's completion is reset before calling async_schedule()
for the device or, in the case of devices with the
power.async_suspend flags unset, before executing the device's
suspend and resume callbacks.
(3) During suspend, right before running the bus type, device type
and device class suspend callbacks for the device, the PM core
waits for the completions of all the device's children to be
completed.
(4) During resume, right before running the bus type, device type and
device class resume callbacks for the device, the PM core waits
for the completion of the device's parent to be completed.
(5) The PM core completes power.completion for each device right
after the bus type, device type and device class suspend (or
resume) callbacks executed for the device have returned.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Add parent information to timing messages

Add parent information to the messages printed by the suspend/resume
core when initcall_debug is set.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

power: fix kernel-doc notation

Warning(drivers/base/power/main.c:453): No description found for parameter 'dev'
Warning(drivers/base/power/main.c:453): No description found for parameter 'cb'
Warning(drivers/base/power/main.c:719): No description found for parameter 'dev'
Warning(drivers/base/power/main.c:719): No description found for parameter 'state'
Warning(drivers/base/power/main.c:719): No description found for parameter 'cb'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

PM: Use pm_runtime_put_sync in system resume

This patch (as1317) fixes a bug in the PM core. When a device is
resumed following a system sleep, the core decrements the device's
runtime PM usage counter but doesn't issue an idle notification if the
counter reaches 0. This could prevent an otherwise unused device from
being runtime-suspended again after the system sleep.

The fix is to call pm_runtime_put_sync() instead of
pm_runtime_put_noidle().

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Measure device suspend and resume times

Measure and print the time of suspending and resuming all devices.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Make the initcall_debug style timing for suspend/resume complete

Commit f2511774863487e61b56a97da07ebf8dd61d7836
(PM: Add initcall_debug style timing for suspend/resume) introduced
basic timing instrumentation, needed for a scritps/bootgraph.pl
equivalent or humans, but it missed the fact that bus types and
device classes which haven't been switched to using struct dev_pm_ops
objects yet need special handling. As a result, the suspend/resume
timing information is only available for devices whose bus types or
device classes use struct dev_pm_ops objects, so the majority of
devices is not covered.

Fix this by adding basic suspend/resume timing instrumentation for
devices whose bus types and device classes still don't use struct
dev_pm_ops objects for power management. To reduce code duplication
move the timing code to helper functions.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: rwsem.h need not be included into main.c

It is not necessary to include <linux/rwsem.h> into
drivers/base/power/main.c, so don't do that.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Remove unnecessary goto from device_resume_noirq()

In device_resume_noirq() there is the 'End' label and the associated
goto statement that aren't strictly necessary, so rework the code to
get rid of them. Also modify device_suspend_noirq() so that it looks
completely analogous to device_resume_noirq().

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Add initcall_debug style timing for suspend/resume

In order to diagnose overall suspend/resume times, we need
basic instrumentation to break down the total time into per
device timing, similar to initcall_debug.

This patch adds the basic timing instrumentation, needed
for a scritps/bootgraph.pl equivalent or humans.
The bootgraph.pl program is still a work in progress, but
is far enough along to know that this patch is sufficient.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Fix warning on suspend errors

Fixes the point where we need to complete the power transition when
device suspend fails, so that we don't print warnings about devices
added to the device hierarchy after a failing suspend.

[rjw: Modified changelog.]

Signed-off-by: Romit Dasgupta <romit@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Reset transition_started at dpm_resume_noirq

transition_started should be set once the preparation of devices for
a PM has started, reset before starting to resume devices. When
resuming devices, kernel calls dpm_resume_noirq then
dpm_resume_end(dpm_resume). Thus we should reset transition_started
at dpm_resume_noirq.

This patch fixes ACPI warning when resuming from suspend/hibernate:

ACPI: \_SB_.PCI0.IDE1.PRI1.MAS1 - docking
------------[ cut here ]------------
WARNING: at drivers/base/power/main.c:87 device_pm_add+0x8b/0xcc()
Hardware name: OptiPlex 760
Device: acpi
Parentless device registered during a PM transaction

[rjw: Fixed up the changelog.]

Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Update kerneldoc comments in drivers/base/power/main.c

The kerneldoc comments in drivers/base/power/main.c are generally
outdated and some of them don't describe the functions very
accurately. Update them and standardize the format to use spaces
instead of tabs.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Alan Stern <stern@rowland.harvard.edu>

PM: Introduce core framework for run-time PM of I/O devices (rev. 17)

Introduce a core framework for run-time power management of I/O
devices. Add device run-time PM fields to 'struct dev_pm_info'
and device run-time PM callbacks to 'struct dev_pm_ops'. Introduce
a run-time PM workqueue and define some device run-time PM helper
functions at the core level. Document all these things.

Special thanks to Alan Stern for his help with the design and
multiple detailed reviews of the pereceding versions of this patch
and to Magnus Damm for testing feedback.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Magnus Damm <damm@igel.co.jp>

Driver Core: Make PM operations a const pointer

They are not supposed to be modified by drivers, so make them const.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

Driver Core: Make PM operations a const pointer

They are not supposed to be modified by drivers, so make them const.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Clear -EAGAIN in dpm_prepare

When the last device in the dpm list is unregistered directly after its
prepare() callback returned with -EAGAIN, the return code is passed to
the calling function, resulting in a suspend failure. Prevent this by
clearing the return code after -EAGAIN.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Remove device_type suspend()/resume()

This patch removes the legacy callbacks ->suspend() and
->resume() from struct device_type. These callbacks seem
unused, and new code should instead make use of struct
dev_pm_ops.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Remove bus_type suspend_late()/resume_early() V2

Remove the ->suspend_late() and ->resume_early() callbacks
from struct bus_type V2. These callbacks are legacy stuff
at this point and since there seem to be no in-tree users
we may as well remove them. New users should use dev_pm_ops.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM core: rename suspend and resume functions

This patch (as1241) renames a bunch of functions in the PM core.
Rather than go through a boring list of name changes, suffice it to
say that in the end we have a bunch of pairs of functions:

device_resume_noirq dpm_resume_noirq
device_resume dpm_resume
device_complete dpm_complete
device_suspend_noirq dpm_suspend_noirq
device_suspend dpm_suspend
device_prepare dpm_prepare

in which device_X does the X operation on a single device and dpm_X
invokes device_X for all devices in the dpm_list.

In addition, the old dpm_power_up and device_resume_noirq have been
combined into a single function (dpm_resume_noirq).

Lastly, dpm_suspend_start and dpm_resume_end are the renamed versions
of the former top-level device_suspend and device_resume routines.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Rename device_power_down/up()

Rename the functions performing "_noirq" dev_pm_ops
operations from device_power_down() and device_power_up()
to device_suspend_noirq() and device_resume_noirq().

The new function names are chosen to show that the functions
are responsible for calling the _noirq() versions to finalize
the suspend/resume operation. The current function names do
not perform power down/up anymore so the names may be misleading.

Global function renames:
- device_power_down() -> device_suspend_noirq()
- device_power_up() -> device_resume_noirq()

Static function renames:
- suspend_device_noirq() -> __device_suspend_noirq()
- resume_device_noirq() -> __device_resume_noirq()

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Len Brown <lenb@kernel.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

PM: Do not hold dpm_list_mtx while disabling/enabling nonboot CPUs

We shouldn't hold dpm_list_mtx while executing
[disable|enable]_nonboot_cpus(), because theoretically this may lead
to a deadlock as shown by the following example (provided by Johannes
Berg):

CPU 3 CPU 2 CPU 1
suspend/hibernate
something:
rtnl_lock() device_pm_lock()
-> mutex_lock(&dpm_list_mtx)

mutex_lock(&dpm_list_mtx)

linkwatch_work
-> rtnl_lock()
disable_nonboot_cpus()
-> flush CPU 3 workqueue

Fortunately, device drivers are supposed to stop any activities that
might lead to the registration of new device objects way before
disable_nonboot_cpus() is called, so it shouldn't be necessary to
hold dpm_list_mtx over the entire late part of device suspend and
early part of device resume.

Thus, during the late suspend and the early resume of devices acquire
dpm_list_mtx only when dpm_list is going to be traversed and release
it right after that.

This patch is reported to fix the regressions tracked as
http://bugzilla.kernel.org/show_bug.cgi?id=13245.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Miles Lane <miles.lane@gmail.com>
Tested-by: Ming Lei <tom.leiming@gmail.com>

PM: Rework handling of interrupts during suspend-resume

Use the functions introduced in by the previous patch,
suspend_device_irqs(), resume_device_irqs() and check_wakeup_irqs(),
to rework the handling of interrupts during suspend (hibernation) and
resume. Namely, interrupts will only be disabled on the CPU right
before suspending sysdevs, while device drivers will be prevented
from receiving interrupts, with the help of the new helper function,
before their "late" suspend callbacks run (and analogously during
resume).

In addition, since the device interrups are now disabled before the
CPU has turned all interrupts off and the CPU will ACK the interrupts
setting the IRQ_PENDING bit for them, check in sysdev_suspend() if
any wake-up interrupts are pending and abort suspend if that's the
case.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Ingo Molnar <mingo@elte.hu>

Driver core: Fix device_move() vs. dpm list ordering, v2

dpm_list currently relies on the fact that child devices will
be registered after their parents to get a correct suspend
order. Using device_move() however destroys this assumption, as
an already registered device may be moved under a newly registered
one.

This patch adds a new argument to device_move(), allowing callers
to specify how dpm_list should be adapted.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: Split up sysdev_[suspend|resume] from device_power_[down|up]

Move the sysdev_suspend/resume from the callee to the callers, with
no real change in semantics, so that we can rework the disabling of
interrupts during suspend/hibernation.

This is based on an earlier patch from Linus.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

driver core: struct device - replace bus_id with dev_name(), dev_set_name()

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: Simplify the new suspend/hibernation framework for devices

PM: Simplify the new suspend/hibernation framework for devices

Following the discussion at the Kernel Summit, simplify the new
device PM framework by merging 'struct pm_ops' and
'struct pm_ext_ops' and removing pointers to 'struct pm_ext_ops'
from 'struct platform_driver' and 'struct pci_driver'.

After this change, the suspend/hibernation callbacks will only
reside in 'struct device_driver' as well as at the bus type/
device class/device type level. Accordingly, PCI and platform
device drivers are now expected to put their suspend/hibernation
callbacks into the 'struct device_driver' embedded in
'struct pci_driver' or 'struct platform_driver', respectively.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

vsprintf: use new vsprintf symbolic function pointer format

Use the '%pF' format to get rid of an "#ifdef DEBUG" and make some printks
atomic.

This removes the last in-tree uses of print_fn_descriptor_symbol(). I
marked print_fn_descriptor_symbol() deprecated and scheduled it for
removal next year to give time for out-of-tree modules to be updated.

parisc's print_fn_descriptor_symbol() is currently broken there (it needs
to dereference the function pointer similar to ia64 and power). This
patch shouldn't make anything worse, but it means we need to fix
dereference_function_descriptor() instead of print_fn_descriptor_symbol()
to get meaningful initcall_debug output.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

debug: use dev_WARN() rather than WARN_ON() in device_pm_add()

device_pm_add() has a WARN_ON that is showing relatively high on
kerneloops.org, but unfortunately the WARN_ON is less than useful
in that it doesn't print any information about what device is causing
the issue.

This patch fixes this by turning the WARN_ON() into the newly
introduces dev_WARN() which will print information about the
device in question.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

x86: memory corruption check - cleanup

Move the prototypes from the generic kernel.h header to the more
appropriate include/asm-x86/bios_ebda.h header file.

Also, remove the check from the power management code - this is a
pure x86 matter for now.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: check for and defend against BIOS memory corruption

Some BIOSes have been observed to corrupt memory in the low 64k. This
change:
- Reserves all memory which does not have to be in that area, to
prevent it from being used as general memory by the kernel. Things
like the SMP trampoline are still in the memory, however.
- Clears the reserved memory so we can observe changes to it.
- Adds a function check_for_bios_corruption() which checks and reports on
memory becoming unexpectedly non-zero. Currently it's called in the
x86 fault handler, and the powermanagement debug output.

Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

PM: Remove WARN_ON from device_pm_add

PM: Remove WARN_ON from device_pm_add

Fix message in device_pm_add() saying that the device will not be
added to dpm_list, although in fact the device is going to be added
to the list regardless of the ordering violation.

Remove the WARN_ON(true) triggered in that situation, because it is
hit by USB very often and spams the users' logs.

This patch fixes bug #11263

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: don't skip device PM init when CONFIG_PM_SLEEP isn't set and CONFIG_PM is set

This patch (as1124) fixes a couple of bugs in the PM core. The new
dev->power.status field should be initialized regardless of whether
CONFIG_PM_SLEEP is enabled, and similarly dpm_sysfs_add() should be
called whenever CONFIG_PM is enabled.

The patch separates out the call to dpm_sysfs_add() from the call to
device_pm_add(). As a result device_pm_add() can no longer return an
error, so its return type is changed to void.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Romit Dasgupta <romit@ti.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Suspend-related patches for 2.6.27

ACPI PM: Add possibility to change suspend sequence

There are some systems out there that don't work correctly with
our current suspend/hibernation code ordering. Provide a workaround
for these systems allowing them to pass 'acpi_sleep=old_ordering' in
the kernel command line so that it will use the pre-ACPI 2.0 ("old")
suspend code ordering.

Unfortunately, this requires us to add a platform hook to the
resuming of devices for recovering the platform in case one of the
device drivers' .suspend() routines returns error code. Namely,
ACPI 1.0 specifies that _PTS should be called before suspending
devices, but _WAK still should be called before resuming them in
order to undo the changes made by _PTS. However, if there is an
error during suspending devices, they are automatically resumed
without returning control to the PM core, so the _WAK has to be
called from within device_resume() in that cases.

The patch also reorders and refactors the ACPI suspend/hibernation
code to avoid duplication as far as reasonably possible.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

Introduce new top level suspend and hibernation callbacks

Introduce 'struct pm_ops' and 'struct pm_ext_ops' ('ext' meaning
'extended') representing suspend and hibernation operations for bus
types, device classes, device types and device drivers.

Modify the PM core to use 'struct pm_ops' and 'struct pm_ext_ops'
objects, if defined, instead of the ->suspend(), ->resume(),
->suspend_late(), and ->resume_early() callbacks (the old callbacks
will be considered as legacy and gradually phased out).

The main purpose of doing this is to separate suspend (aka S2RAM and
standby) callbacks from hibernation callbacks in such a way that the
new callbacks won't take arguments and the semantics of each of them
will be clearly specified. This has been requested for multiple
times by many people, including Linus himself, and the reason is that
within the current scheme if ->resume() is called, for example, it's
difficult to say why it's been called (ie. is it a resume from RAM or
from hibernation or a suspend/hibernation failure etc.?).

The second purpose is to make the suspend/hibernation callbacks more
flexible so that device drivers can handle more than they can within
the current scheme. For example, some drivers may need to prevent
new children of the device from being registered before their
->suspend() callbacks are executed or they may want to carry out some
operations requiring the availability of some other devices, not
directly bound via the parent-child relationship, in order to prepare
for the execution of ->suspend(), etc.

Ultimately, we'd like to stop using the freezing of tasks for suspend
and therefore the drivers' suspend/hibernation code will have to take
care of the handling of the user space during suspend/hibernation.
That, in turn, would be difficult within the current scheme, without
the new ->prepare() and ->complete() callbacks.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

Clean up 'print_fn_descriptor_symbol()' types

Everybody wants to pass it a function pointer, and in fact, that is what
you _must_ pass it for it to make sense (since it knows that ia64 and
ppc64 use descriptors for function pointers and fetches the actual
address from there).

So don't make the argument be a 'unsigned long' and force everybody to
add a cast.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Relax check on adding children of suspended devices

Do not refuse to actually register children of suspended devices,
but still warn about attempts to do that.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

PM: Remove destroy_suspended_device()

After 2.6.24 there was a plan to make the PM core acquire all device
semaphores during a suspend/hibernation to protect itself from
concurrent operations involving device objects. That proved to be
too heavy-handed and we found a better way to achieve the goal, but
before it happened, we had introduced the functions
device_pm_schedule_removal() and destroy_suspended_device() to allow
drivers to "safely" destroy a suspended device and we had adapted some
drivers to use them. Now that these functions are no longer necessary,
it seems reasonable to remove them and modify their users to use the
normal device unregistration instead.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: Make wakeup flags available whenever CONFIG_PM is set

The various wakeup flags and their accessor macros in struct
dev_pm_info should be available whenever CONFIG_PM is enabled, not
just when CONFIG_PM_SLEEP is on. Otherwise remote wakeup won't always
be configurable for runtime power management. This patch (as1056b)
fixes the oversight.

David Brownell adds:
More accurately, fixes the "regression" ... as noted sometime
last summer, after 296699de6bdc717189a331ab6bbe90e05c94db06
introduced CONFIG_SUSPEND. But that didn't make the regression
list for that kernel, ergo the delay in fixing it.

[rjw: rebased]

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Driver core: Call device_pm_add() after bus_add_device() in device_add()

Include dpm_sysfs_add() into device_pm_add(), in analogy with
device_pm_remove(), and modify device_add() to call the latter after
bus_add_device(), to avoid situations in which the PM core may
attempt to suspend a device the registration of which has not been
successful.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: Handle device registrations during suspend/resume

Modify the PM core to protect its data structures, specifically the
dpm_active list, from being corrupted if a child of the currently
suspending device is registered concurrently with its ->suspend()
callback. In that case, since the new device (the child) is added
to dpm_active after its parent, the PM core will attempt to
suspend it after the parent, which is wrong.

Introduce a new member of struct dev_pm_info, called 'sleeping',
and use it to check if the parent of the device being added to
dpm_active has been suspended, in which case the device registration
fails. Also, use 'sleeping' for checking if the ordering of devices
on dpm_active is correct.

Introduce variable 'all_sleeping' that will be set to 'true' once all
devices have been suspended and make new device registrations fail
until 'all_sleeping' is reset to 'false', in order to avoid having
unsuspended devices around while the system is going into a sleep state.

Remove pm_sleep_rwsem which is not necessary any more.

Special thanks to Alan Stern for discussions and suggestions that
lead to the creation of this patch.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

power_state: remove it from driver core

power_state is scheduled for removal, and it is used only for debug
prints by driver core. Remove it.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: fix new mutex-locking bug in the PM core

This patch (as1041) fixes a bug introduced by the
acquire-all-device-semaphores reversion. The error pathway of
dpm_suspend() fails to reacquire a mutex it should be holding.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: Do not acquire device semaphores upfront during suspend

Remove the code that acquires all device semaphores from the suspend
code path as it causes multiple problems to appear (most notably,
http://bugzilla.kernel.org/show_bug.cgi?id=10030) and revert the
change introduced by commit 4145ed6dc597a9bea5f6ae8c574653b2de10620f
depending on the code being removed.

Remove pm_sleep_lock()/pm_sleep_unlock() from device_add() to avoid
the issue reported at http://bugzilla.kernel.org/show_bug.cgi?id=9874.

It should fix the regreesions reported at:
http://bugzilla.kernel.org/show_bug.cgi?id=9874
http://bugzilla.kernel.org/show_bug.cgi?id=10030

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: Remove unbalanced mutex_unlock() from dpm_resume()

Remove an unnecessary unlocking of dpm_list_mtx in the error path
in drivers/base/power/main.c:dpm_suspend() .

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

driver-core: fix kernel-doc function parameters

Fix drivers/base/ missing kernel-doc parameters:
Warning(linux-2.6.24-git12//drivers/base/driver.c:133): No description found for parameter 'drv'
Warning(linux-2.6.24-git12//drivers/base/driver.c:133): No description found for parameter 'kobj'
Warning(linux-2.6.24-git12//drivers/base/driver.c:133): No description found for parameter 'fmt'
Warning(linux-2.6.24-git12//drivers/base/power/main.c:530): No description found for parameter 'state'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: Make suspend_device() static

suspend_device() can become static.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>

PM: Export device_pm_schedule_removal

Move the declaration of device_pm_schedule_removal() to device.h
and make it exported, as it will be used directly by some drivers
for unregistering device objects during suspend/resume cycles in a
safe way.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: Acquire device locks on suspend

This patch reorganizes the way suspend and resume notifications are
sent to drivers. The major changes are that now the PM core acquires
every device semaphore before calling the methods, and calls to
device_add() during suspends will fail, while calls to device_del()
during suspends will block.

It also provides a way to safely remove a suspended device with the
help of the PM core, by using the device_pm_schedule_removal() callback
introduced specifically for this purpose, and updates two drivers (msr
and cpuid) that need to use it.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

create /sys/.../power when CONFIG_PM is set

The CONFIG_SUSPEND changes in 2.6.23 caused a regression under certain
configuration conditions (SUSPEND=n, USB_AUTOSUSPEND=y) where all USB
device attributes in sysfs (idVendor, idProduct, ...) silently disappeared,
causing udev breakage and more.

The cause of this is that the /sys/.../power subdirectory is now only
created when CONFIG_PM_SLEEP is set, however, it should be created whenever
CONFIG_PM is set to handle the above situation. The following patch fixes
the regression.

Signed-off-by: Daniel Drake <dsd@gentoo.org>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: merge device power-management source files

This patch (as993) merges the suspend.c and resume.c files in
drivers/base/power into main.c, making some public symbols private.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PM: Remove pm_parent from struct dev_pm_info

The pm_parent member of struct dev_pm_info (defined in include/linux/pm.h) is
only used to check if the device's parent is in the right state while the
device is being suspended or resumed. However, this can be done just as well
with the help of the parent pointer in struct device, so pm_parent can be
removed along with some code that handles it.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Power Management: use mutexes instead of semaphores

The Power Management code uses semaphores as mutexes. Use the mutex API
instead of the (binary) semaphores.

Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

define platform wakeup hook, use in pci_enable_wake()

This defines a platform hook to enable/disable a device as a wakeup event
source. It's initially for use with ACPI, but more generally it could be used
whenever enable_irq_wake()/disable_irq_wake() don't suffice.

The hook is called -- if available -- inside pci_enable_wake(); and the
semantics of that call are enhanced so that support for PCI PME# is no longer
needed. It can now work for devices with "legacy PCI PM", when platform
support allows it. (That support would use some board-specific signal for for
the same purpose as PME#.)

[akpm@linux-foundation.org: Make it compile with CONFIG_PM=n]
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] PM: use kobject_name() to access kobject names

Noone should use kobj.name directly since it may contain garbage.
Objects with longer names have them stored in separately allocated
memory pointed to by kobj->k_name.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Remove obsolete #include <linux/config.h>

Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

[PATCH] one less word in struct device

This saves a word from "struct device" ... there's a refcounting mechanism
stub that's rather ineffective (the values are never even tested!), which
can safely be deleted. With this patch it uses normal device refcounting,
so any potential users of the pm_parent mechanism will be more correct.
(That mechanism is actually unusable for now though; it does nothing.)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/base/power/main.c | 26 +++-----------------------
include/linux/pm.h | 1 -
2 files changed, 3 insertions(+), 24 deletions(-)

Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!