drm/nouveau/disp: add output backlight control methods

- preparation for GSP-RM

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Acked-by: Danilo Krummrich <me@dakr.org>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230919220442.202488-24-lyude@redhat.com

drm/nouveau/kms: Fix backlight registration

The nouveau code used to call drm_fb_helper_initial_config() from
nouveau_fbcon_init() before calling drm_dev_register(). This would
probe all connectors so that drm_connector->status could be used during
backlight registration which runs from nouveau_connector_late_register().

After commit 4a16dd9d18a0 ("drm/nouveau/kms: switch to drm fbdev helpers")
the fbdev emulation code, which now is a drm-client, can only run after
drm_dev_register(). So during backlight registration the connectors are
not probed yet and the drm_connector->status == connected check in
nv50_backlight_init() would now always fail.

Replace the drm_connector->status == connected check with
a drm_helper_probe_detect() == connected check to fix nv_backlight
no longer getting registered because of this.

Fixes: 4a16dd9d18a0 ("drm/nouveau/kms: switch to drm fbdev helpers")
Link: https://gitlab.freedesktop.org/drm/nouveau/-/issues/202
Link: https://bugzilla.redhat.com/show_bug.cgi?id=2181941
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230326205433.36485-1-hdegoede@redhat.com

drm/nouveau: Add support to control backlight using bl_power for nva3.

Summary:

* Add support to turn on/off backlight when changing values in bl_power
file. This is achieved by using function backlight_get_brightness()
in nva3_set_intensity to get current brightness.

Test plan:

* Turn off:
echo 1 > /sys/class/backlight/nv_backlight/bl_power

* Turn on:
echo 0 > /sys/class/backlight/nv_backlight/bl_power

Signed-off-by: Antonio Gomes <antoniospg100@gmail.com>
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221104220424.41164-1-antoniospg100@gmail.com

drm/nouveau: Register ACPI video backlight when nv_backlight registration fails (v2)

Typically the acpi_video driver will initialize before nouveau, which
used to cause /sys/class/backlight/acpi_video0 to get registered and then
nouveau would register its own nv_backlight device later. After which
the drivers/acpi/video_detect.c code unregistered the acpi_video0 device
to avoid there being 2 backlight devices.

This means that userspace used to briefly see 2 devices and the
disappearing of acpi_video0 after a brief time confuses the systemd
backlight level save/restore code, see e.g.:
https://bbs.archlinux.org/viewtopic.php?id=269920

To fix this the ACPI video code has been modified to make backlight class
device registration a separate step, relying on the drm/kms driver to
ask for the acpi_video backlight registration after it is done setting up
its native backlight device.

Add a call to the new acpi_video_register_backlight() when native backlight
device registration has failed / was skipped to ensure that there is a
backlight device available before the drm_device gets registered with
userspace.

Changes in v2:
- Add nouveau_acpi_video_register_backlight() wrapper to avoid unresolved
symbol errors on non X86

Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drm/nouveau: Don't register backlight when another backlight should be used (v2)

Before this commit when we want userspace to use the acpi_video backlight
device we register both the GPU's native backlight device and acpi_video's
firmware acpi_video# backlight device. This relies on userspace preferring
firmware type backlight devices over native ones.

Registering 2 backlight devices for a single display really is
undesirable, don't register the GPU's native backlight device when
another backlight device should be used.

Changes in v2:
- Add nouveau_acpi_video_backlight_use_native() wrapper to avoid unresolved
symbol errors on non X86

Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drm/nouveau: Fix a potential theorical leak in nouveau_get_backlight_name()

If successful ida_simple_get() calls are not undone when needed, some
additional memory may be allocated and wasted.

Here, an ID between 0 and MAX_INT is required. If this ID is >=100, it is
not taken into account and is wasted. It should be released.

Instead of calling ida_simple_remove(), take advantage of the 'max'
parameter to require the ID not to be too big. Should it be too big, it
is not allocated and don't need to be freed.

While at it, use ida_alloc_xxx()/ida_free() instead to
ida_simple_get()/ida_simple_remove().
The latter is deprecated and more verbose.

Fixes: db1a0ae21461 ("drm/nouveau/bl: Assign different names to interfaces")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Lyude Paul <lyude@redhat.com>
[Fixed formatting warning from checkpatch]
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/9ba85bca59df6813dc029e743a836451d5173221.1644386541.git.christophe.jaillet@wanadoo.fr

drm/nouveau/backlight: Just set all backlight types as RAW

Currently we can get a warning on systems with eDP backlights like so:

nv_backlight: invalid backlight type
WARNING: CPU: 4 PID: 454 at drivers/video/backlight/backlight.c:420
backlight_device_register+0x226/0x250

This happens as a result of us not filling out props.type for the eDP
backlight, even though we do it for all other backlight types.

Since nothing in our driver uses anything but BACKLIGHT_RAW, let's take the
props\.type assignments out of the codepaths for individual backlight types
and just set it unconditionally to prevent this from happening again.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Fixes: 6eca310e8924 ("drm/nouveau/kms/nv50-: Add basic DPCD backlight support for nouveau")
Cc: <stable@vger.kernel.org> # v5.15+
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220204193319.451119-1-lyude@redhat.com

drm/nouveau/backlight: Fix LVDS backlight detection on some laptops

It seems that some laptops will report having both an eDP and LVDS
connector, even though only the LVDS connector is actually hooked up. This
can lead to issues with backlight registration if the eDP connector ends up
getting registered before the LVDS connector, as the backlight device will
then be registered to the eDP connector instead of the LVDS connector.

So, fix this by only registering the backlight on connectors that are
reported as being connected.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Fixes: 6eca310e8924 ("drm/nouveau/kms/nv50-: Add basic DPCD backlight support for nouveau")
Bugzilla: https://gitlab.freedesktop.org/drm/nouveau/-/issues/137
Cc: <stable@vger.kernel.org> # v5.15+
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220204180504.328999-1-lyude@redhat.com

drm/nouveau/kms/nv50-: Explicitly check DPCD backlights for aux enable/brightness

Since we don't support hybrid AUX/PWM backlights in nouveau right now,
let's add some explicit checks so that we don't break nouveau once we
enable support for these backlights in other drivers.

Reviewed-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211105183342.130810-3-lyude@redhat.com

drm/nouveau/kms/nv50-: Add basic DPCD backlight support for nouveau

This adds support for controlling panel backlights over eDP using VESA's
standard backlight control interface. Luckily, Nvidia was cool enough to
never come up with their own proprietary backlight control interface (at
least, not any that I or the laptop manufacturers I've talked to are aware
of), so this should work for any laptop panels which support the VESA
backlight control interface.

Note that we don't yet provide the panel backlight frequency to the DRM DP
backlight helpers. This should be fine for the time being, since it's not
required to get basic backlight controls working.

For reference: there's some mentions of PWM backlight values in
nouveau_reg.h, but I'm not sure these are the values we would want to use.
If we figure out how to get this information in the future, we'll have the
benefit of more granular backlight control.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: greg.depoire@gmail.com
Link: https://patchwork.freedesktop.org/patch/msgid/20210514181504.565252-10-lyude@redhat.com

drm/nouveau/core: recognise GA10[024]

GA100 hidden behind a module option, as it's not been as well verified
since initial bring-up and may need additional changes.

There's no display anyway, so this can wait for a bit.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau: register backlight on pascal and newer

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau: Refactor nvXX_backlight_init()

There's literally no difference between any of the backlight init
functions besides the backlight properties they set and the backlight
callbacks that they set, so move all of the duplicated backlight init
code out of there and into nouveau_backlight_init().

This gets rid of a lot of copy pasta!

Changes since v1:
- Some of the pre-refactor callbacks were storing nv_encoder in callback
data for the backlight devices that they registered, as opposed to
nouveau_drm. This got missed and caused some bugs that didn't
originally appear on my setup (NULL kernel derefs) for some reason.
So, fix this by finding the nouveau_encoder in
nouveau_backlight_init(), and using that as the callback data for all
gens instead even if they don't care about the encoder.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Jeffery Miller <jmiller@neverware.com>
Cc: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau: Cleanup indenting in nouveau_backlight.c

Still no functional changes.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau/drm/nouveau: s/nouveau_backlight_exit/nouveau_backlight_fini/

More consistent with the rest of the codebase, no functional changes
here.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau: Move backlight device into nouveau_connector

Currently module unloading is broken in nouveau due to a rather annoying
race condition resulting from nouveau_backlight.c having gone a bit
stale over time:

[ 1960.791143] ==================================================================
[ 1960.791394] BUG: KASAN: use-after-free in nouveau_backlight_exit+0x112/0x150 [nouveau]
[ 1960.791460] Read of size 4 at addr ffff88075accf350 by task zsh/11185
[ 1960.791521]
[ 1960.791545] CPU: 7 PID: 11185 Comm: zsh Kdump: loaded Tainted: G O 4.18.0Lyude-Test+ #4
[ 1960.791580] Hardware name: LENOVO 20EQS64N0B/20EQS64N0B, BIOS N1EET79W (1.52 ) 07/13/2018
[ 1960.791628] Call Trace:
[ 1960.791680] dump_stack+0xa4/0xfd
[ 1960.791721] print_address_description+0x71/0x239
[ 1960.791833] ? nouveau_backlight_exit+0x112/0x150 [nouveau]
[ 1960.791877] kasan_report.cold.6+0x242/0x2fe
[ 1960.791919] __asan_report_load4_noabort+0x19/0x20
[ 1960.792012] nouveau_backlight_exit+0x112/0x150 [nouveau]
[ 1960.792081] nouveau_display_destroy+0x76/0x150 [nouveau]
[ 1960.792150] nouveau_drm_device_fini+0xb7/0x190 [nouveau]
[ 1960.792265] nouveau_drm_device_remove+0x14b/0x1d0 [nouveau]
[ 1960.792347] ? nouveau_cli_work_queue+0x2e0/0x2e0 [nouveau]
[ 1960.792378] ? trace_hardirqs_on_caller+0x38b/0x570
[ 1960.792406] ? trace_hardirqs_on+0xd/0x10
[ 1960.792472] nouveau_drm_remove+0x37/0x50 [nouveau]
[ 1960.792502] pci_device_remove+0x112/0x2d0
[ 1960.792530] ? pcibios_free_irq+0x10/0x10
[ 1960.792558] ? kasan_check_write+0x14/0x20
[ 1960.792587] device_release_driver_internal+0x35c/0x650
[ 1960.792617] device_release_driver+0x12/0x20
[ 1960.792643] pci_stop_bus_device+0x172/0x1e0
[ 1960.792671] pci_stop_and_remove_bus_device_locked+0x1a/0x30
[ 1960.792715] remove_store+0xcb/0xe0
[ 1960.792753] ? sriov_numvfs_store+0x2e0/0x2e0
[ 1960.792779] ? __lock_is_held+0xb5/0x140
[ 1960.792808] ? component_add+0x530/0x530
[ 1960.792834] dev_attr_store+0x3f/0x70
[ 1960.792859] ? sysfs_file_ops+0x11d/0x170
[ 1960.792885] sysfs_kf_write+0x104/0x150
[ 1960.792915] ? sysfs_file_ops+0x170/0x170
[ 1960.792940] kernfs_fop_write+0x24f/0x400
[ 1960.792978] ? __lock_acquire+0x6ea/0x47f0
[ 1960.793021] __vfs_write+0xeb/0x760
[ 1960.793048] ? kernel_read+0x130/0x130
[ 1960.793076] ? __lock_is_held+0xb5/0x140
[ 1960.793107] ? rcu_read_lock_sched_held+0xdd/0x110
[ 1960.793135] ? rcu_sync_lockdep_assert+0x78/0xb0
[ 1960.793162] ? __sb_start_write+0x183/0x220
[ 1960.793189] vfs_write+0x14d/0x4a0
[ 1960.793229] ksys_write+0xd2/0x1b0
[ 1960.793255] ? __ia32_sys_read+0xb0/0xb0
[ 1960.793298] ? fput+0x1d/0x120
[ 1960.793324] ? filp_close+0xf3/0x130
[ 1960.793349] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe
[ 1960.793380] __x64_sys_write+0x73/0xb0
[ 1960.793407] do_syscall_64+0xaa/0x400
[ 1960.793433] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 1960.793460] RIP: 0033:0x7f59df433164
[ 1960.793486] Code: 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8d 05 81 38 2d 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 41 54 49 89 d4 55 48 89 f5 53
[ 1960.793541] RSP: 002b:00007ffd70ee2fb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 1960.793576] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f59df433164
[ 1960.793620] RDX: 0000000000000002 RSI: 00005578088640c0 RDI: 0000000000000001
[ 1960.793665] RBP: 00005578088640c0 R08: 00007f59df7038c0 R09: 00007f59e0995b80
[ 1960.793696] R10: 000000000000000a R11: 0000000000000246 R12: 00007f59df702760
[ 1960.793730] R13: 0000000000000002 R14: 00007f59df6fd760 R15: 0000000000000002
[ 1960.793768]
[ 1960.793790] Allocated by task 11167:
[ 1960.793816] save_stack+0x43/0xd0
[ 1960.793841] kasan_kmalloc+0xc4/0xe0
[ 1960.793880] kasan_slab_alloc+0x11/0x20
[ 1960.793905] kmem_cache_alloc+0xd7/0x270
[ 1960.793944] getname_flags+0xbd/0x520
[ 1960.793969] user_path_at_empty+0x23/0x50
[ 1960.793994] do_faccessat+0x1fc/0x5d0
[ 1960.794018] __x64_sys_access+0x59/0x80
[ 1960.794043] do_syscall_64+0xaa/0x400
[ 1960.794067] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 1960.794093]
[ 1960.794127] Freed by task 11167:
[ 1960.794152] save_stack+0x43/0xd0
[ 1960.794190] __kasan_slab_free+0x139/0x190
[ 1960.794215] kasan_slab_free+0xe/0x10
[ 1960.794239] kmem_cache_free+0xcb/0x2c0
[ 1960.794264] putname+0xad/0xe0
[ 1960.794287] filename_lookup.part.59+0x1f1/0x360
[ 1960.794313] user_path_at_empty+0x3e/0x50
[ 1960.794338] do_faccessat+0x1fc/0x5d0
[ 1960.794362] __x64_sys_access+0x59/0x80
[ 1960.794393] do_syscall_64+0xaa/0x400
[ 1960.794421] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 1960.794461]
[ 1960.794483] The buggy address belongs to the object at ffff88075acceac0
[ 1960.794483] which belongs to the cache names_cache of size 4096
[ 1960.794540] The buggy address is located 2192 bytes inside of
[ 1960.794540] 4096-byte region [ffff88075acceac0, ffff88075accfac0)
[ 1960.794581] The buggy address belongs to the page:
[ 1960.794609] page:ffffea001d6b3200 count:1 mapcount:0 mapping:ffff880778e4b1c0 index:0x0 compound_mapcount: 0
[ 1960.794651] flags: 0x8000000000008100(slab|head)
[ 1960.794679] raw: 8000000000008100 ffffea001d39e808 ffffea001d39ea08 ffff880778e4b1c0
[ 1960.794739] raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000
[ 1960.794785] page dumped because: kasan: bad access detected
[ 1960.794813]
[ 1960.794834] Memory state around the buggy address:
[ 1960.794861] ffff88075accf200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 1960.794894] ffff88075accf280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 1960.794925] >ffff88075accf300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 1960.794956] ^
[ 1960.794985] ffff88075accf380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 1960.795017] ffff88075accf400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 1960.795061] ==================================================================
[ 1960.795106] Disabling lock debugging due to kernel taint
[ 1960.795131] ------------[ cut here ]------------
[ 1960.795148] ida_remove called for id=1802201963 which is not allocated.
[ 1960.795193] WARNING: CPU: 7 PID: 11185 at lib/idr.c:521 ida_remove+0x184/0x210
[ 1960.795213] Modules linked in: nouveau(O) mxm_wmi ttm i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm joydev vfat fat intel_rapl x86_pkg_temp_thermal coretemp crc32_pclmul iTCO_wdt psmouse wmi_bmof mei_me tpm_tis mei tpm_tis_core tpm i2c_i801 thinkpad_acpi pcc_cpufreq crc32c_intel serio_raw xhci_pci xhci_hcd wmi video i2c_dev i2c_core
[ 1960.795305] CPU: 7 PID: 11185 Comm: zsh Kdump: loaded Tainted: G B O 4.18.0Lyude-Test+ #4
[ 1960.795330] Hardware name: LENOVO 20EQS64N0B/20EQS64N0B, BIOS N1EET79W (1.52 ) 07/13/2018
[ 1960.795352] RIP: 0010:ida_remove+0x184/0x210
[ 1960.795370] Code: 4c 89 f7 e8 ae c8 00 00 eb 22 41 83 c4 02 4c 89 e8 41 83 fc 3f 0f 86 64 ff ff ff 44 89 fe 48 c7 c7 20 94 1e 83 e8 54 ed 81 fe <0f> 0b 48 b8 00 00 00 00 00 fc ff df 48 01 c3 c7 03 00 00 00 00 c7
[ 1960.795402] RSP: 0018:ffff88074d4df7b8 EFLAGS: 00010082
[ 1960.795421] RAX: 0000000000000000 RBX: 1ffff100e9a9befa RCX: ffffffff81479975
[ 1960.795440] RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff88077c1de690
[ 1960.795460] RBP: ffff88074d4df878 R08: ffffed00ef83bcd3 R09: ffffed00ef83bcd2
[ 1960.795479] R10: ffffed00ef83bcd2 R11: ffff88077c1de697 R12: 000000000000036b
[ 1960.795498] R13: 0000000000000202 R14: ffffffffa0aa7fa0 R15: 000000006b6b6b6b
[ 1960.795518] FS: 00007f59e0995b80(0000) GS:ffff88077c1c0000(0000) knlGS:0000000000000000
[ 1960.795553] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1960.795571] CR2: 00007f59e09a2010 CR3: 00000004a1a70005 CR4: 00000000003606e0
[ 1960.795596] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1960.795629] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1960.795649] Call Trace:
[ 1960.795667] ? ida_destroy+0x1d0/0x1d0
[ 1960.795686] ? kasan_check_write+0x14/0x20
[ 1960.795704] ? do_raw_spin_lock+0xc2/0x1c0
[ 1960.795724] ida_simple_remove+0x26/0x40
[ 1960.795794] nouveau_backlight_exit+0x9d/0x150 [nouveau]
[ 1960.795867] nouveau_display_destroy+0x76/0x150 [nouveau]
[ 1960.795930] nouveau_drm_device_fini+0xb7/0x190 [nouveau]
[ 1960.795989] nouveau_drm_device_remove+0x14b/0x1d0 [nouveau]
[ 1960.796047] ? nouveau_cli_work_queue+0x2e0/0x2e0 [nouveau]
[ 1960.796067] ? trace_hardirqs_on_caller+0x38b/0x570
[ 1960.796089] ? trace_hardirqs_on+0xd/0x10
[ 1960.796146] nouveau_drm_remove+0x37/0x50 [nouveau]
[ 1960.796167] pci_device_remove+0x112/0x2d0
[ 1960.796186] ? pcibios_free_irq+0x10/0x10
[ 1960.796218] ? kasan_check_write+0x14/0x20
[ 1960.796237] device_release_driver_internal+0x35c/0x650
[ 1960.796257] device_release_driver+0x12/0x20
[ 1960.796289] pci_stop_bus_device+0x172/0x1e0
[ 1960.796308] pci_stop_and_remove_bus_device_locked+0x1a/0x30
[ 1960.796328] remove_store+0xcb/0xe0
[ 1960.796345] ? sriov_numvfs_store+0x2e0/0x2e0
[ 1960.796364] ? __lock_is_held+0xb5/0x140
[ 1960.796383] ? component_add+0x530/0x530
[ 1960.796401] dev_attr_store+0x3f/0x70
[ 1960.796419] ? sysfs_file_ops+0x11d/0x170
[ 1960.796436] sysfs_kf_write+0x104/0x150
[ 1960.796454] ? sysfs_file_ops+0x170/0x170
[ 1960.796471] kernfs_fop_write+0x24f/0x400
[ 1960.796488] ? __lock_acquire+0x6ea/0x47f0
[ 1960.796520] __vfs_write+0xeb/0x760
[ 1960.796538] ? kernel_read+0x130/0x130
[ 1960.796556] ? __lock_is_held+0xb5/0x140
[ 1960.796590] ? rcu_read_lock_sched_held+0xdd/0x110
[ 1960.796608] ? rcu_sync_lockdep_assert+0x78/0xb0
[ 1960.796626] ? __sb_start_write+0x183/0x220
[ 1960.796648] vfs_write+0x14d/0x4a0
[ 1960.796666] ksys_write+0xd2/0x1b0
[ 1960.796684] ? __ia32_sys_read+0xb0/0xb0
[ 1960.796701] ? fput+0x1d/0x120
[ 1960.796732] ? filp_close+0xf3/0x130
[ 1960.796749] ? entry_SYSCALL_64_after_hwframe+0x59/0xbe
[ 1960.796768] __x64_sys_write+0x73/0xb0
[ 1960.796800] do_syscall_64+0xaa/0x400
[ 1960.796818] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 1960.796836] RIP: 0033:0x7f59df433164
[ 1960.796854] Code: 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8d 05 81 38 2d 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 41 54 49 89 d4 55 48 89 f5 53
[ 1960.796884] RSP: 002b:00007ffd70ee2fb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 1960.796906] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f59df433164
[ 1960.796926] RDX: 0000000000000002 RSI: 00005578088640c0 RDI: 0000000000000001
[ 1960.796946] RBP: 00005578088640c0 R08: 00007f59df7038c0 R09: 00007f59e0995b80
[ 1960.796966] R10: 000000000000000a R11: 0000000000000246 R12: 00007f59df702760
[ 1960.796985] R13: 0000000000000002 R14: 00007f59df6fd760 R15: 0000000000000002
[ 1960.797008] irq event stamp: 509990
[ 1960.797026] hardirqs last enabled at (509989): [<ffffffff8119ff78>] flush_work+0x4b8/0x6d0
[ 1960.797063] hardirqs last disabled at (509990): [<ffffffff8297c395>] _raw_spin_lock_irqsave+0x25/0x60
[ 1960.797085] softirqs last enabled at (509744): [<ffffffff82c005ad>] __do_softirq+0x5ad/0x8c0
[ 1960.797121] softirqs last disabled at (509735): [<ffffffff8115aa15>] irq_exit+0x1a5/0x1e0
[ 1960.797142] ---[ end trace fb1342325f1846b8 ]---

While I haven't actually gone into the details of what's causing this to
happen (maybe the kernel removes the backlight device in the device core
before we get to it?), it doesn't really matter anyway because the way
nouveau handles backlights has long since been deprecated.

According to the documentation on the drm_connector->late_register()
hook, the ->late_register() hook should be used for adding extra
connector-related devices. Vice versa, the ->early_unregister() hook is
meant to be used for removing those devices.

So: gut nouveau_drm->bl_list and nouveau_drm->backlight, and replace
them with per-connector backlight structures. Additionally, move
backlight registration/teardown into the ->late_register() and
->early_unregister() hooks so that DRM can give us a chance to remove
the backlight before the connector is even removed. This appears to fix
the problem once and for all.

Changes since v2:
- Use NV_INFO_ONCE for printing GMUX information, since otherwise this
will end up printing that message for as many times as we have
connectors

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau: Check backlight IDs are >= 0, not > 0

Remember, ida IDs start at 0, not 1!

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau: Use drm_connector_list_iter_* for iterating connectors

Every codepath in nouveau that loops through the connector list
currently does so using the old method, which is prone to race
conditions from MST connectors being created and destroyed. This has
been causing a multitude of problems, including memory corruption from
trying to access connectors that have already been freed!

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: stable@vger.kernel.org
Cc: Karol Herbst <karolherbst@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau/bl: fix backlight regression

Fixes: 3c66c87dc9 ("drm/nouveau/disp: remove hw-specific customisation
of output paths")
Suggested-by: Ben Skeggs <skeggsb@redhat.com>
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau/bl: Fix oops on driver unbind

Unbinding nouveau on a dual GPU MacBook Pro oopses because we iterate
over the bl_connectors list in nouveau_backlight_exit() but skipped
initializing it in nouveau_backlight_init(). Stacktrace for posterity:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
IP: nouveau_backlight_exit+0x2b/0x70 [nouveau]
nouveau_display_destroy+0x29/0x80 [nouveau]
nouveau_drm_unload+0x65/0xe0 [nouveau]
drm_dev_unregister+0x3c/0xe0 [drm]
drm_put_dev+0x2e/0x60 [drm]
nouveau_drm_device_remove+0x47/0x70 [nouveau]
pci_device_remove+0x36/0xb0
device_release_driver_internal+0x157/0x220
driver_detach+0x39/0x70
bus_remove_driver+0x51/0xd0
pci_unregister_driver+0x2a/0xa0
nouveau_drm_exit+0x15/0xfb0 [nouveau]
SyS_delete_module+0x18c/0x290
system_call_fast_compare_end+0xc/0x6f

Fixes: b53ac1ee12a3 ("drm/nouveau/bl: Do not register interface if Apple GMUX detected")
Cc: stable@vger.kernel.org # v4.10+
Cc: Pierre Moreau <pierre.morrow@free.fr>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau: allocate device object for every client

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau/bl: Do not register interface if Apple GMUX detected

The Apple GMUX is the one managing the backlight, so there is no need for
Nouveau to register its own backlight interface.

v2: Do not split information message on two lines as it prevents from grepping
it, as pointed out by Lukas Wunner

v3: Add a missing end-of-line character to the printed message

Signed-off-by: Pierre Moreau <pierre.morrow@free.fr>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau/bl: Assign different names to interfaces

Currently, every backlight interface created by Nouveau uses the same name,
nv_backlight. This leads to a sysfs warning as it tries to create an already
existing folder. This patch adds a incremented number to the name, but keeps
the initial name as nv_backlight, to avoid possibly breaking userspace; the
second interface will be named nv_backlight1, and so on.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=86539

v2:
* Switch to using ida for generating unique IDs, as suggested by Ilia Mirkin;
* Allocate backlight name on the stack, as suggested by Ilia Mirkin;
* Move `nouveau_get_backlight_name()` to avoid forward declaration, as
suggested by Ilia Mirkin;
* Fix reference to bug report formatting, as reported by Nick Tenney.

v3:
* Define a macro for the size of the backlight name, to avoid defining
it multiple times;
* Use snprintf in place of sprintf.

v4:
* Do not create similarly named interfaces when reaching the maximum
amount of unique names, but fail instead, as pointed out by Lukas Wunner

Signed-off-by: Pierre Moreau <pierre.morrow@free.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau/kms: add Maxwell to backlight initialization

Signed-off-by: Faris Alsalama <farisbenbrahem@gmail.com>
Acked-by: Acked-by: Pierre Moreau <pierre.morrow@free.fr>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau: rename nouveau_drm.h to nouveau_drv.h

Fixes out-of-tree build issue where uapi/drm/nouveau_drm.h gets picked
up instead.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau/nvif: simplify and tidy library interfaces

A variety of tweaks to the NVIF library interfaces, mostly ripping out
things that turned out to be not so useful.

- Removed refcounting from nvif_object, callers are expected to not be
stupid instead.
- nvif_client is directly reachable from anything derived from nvif_object,
removing the need for heuristics to locate it
- _new() versions of interfaces, that allocate memory for the object
they construct, have been removed. The vast majority of callers used
the embedded _init() interfaces.
- No longer storing constructor arguments (and the data returned from
nvkm) inside nvif_object, it's more or less unused and just wastes
memory.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau: initial pass at moving to struct nvif_device

This is an attempt at isolating some of the changes necessary to port
to NVIF in a separate commit.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau: kill nouveau_dev() + wrap register macros

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau/core: remove NV_D0 family

The one place where it mattered has been replaced with a class check,
which is more appropriate anyway.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

nouveau: Don't check acpi_video_backlight_support() before registering backlight

acpi_video_backlight_support() is supposed to be called by other (vendor
specific) firmware backlight controls, not by native / raw backlight controls
like nv_backlight.

Userspace will normally prefer firmware interfaces over raw interfaces, so
if acpi_video backlight support is present it will use that even if
nv_backlight is registered as well.

Except when video.use_native_backlight is present on the kernel cmdline
(or enabled through a dmi based quirk). As the name indicates the goal here
is to make only the raw interface available to userspace so that it will use
that (it only does this when it sees a win8 compliant bios).

This is done by:
1) Not registering any acpi_video# backlight devices; and
2) Making acpi_video_backlight_support() return true so that other firmware
drivers, ie acer_wmi, thinkpad_acpi, dell_laptop, etc. Don't register their
own vender specific interfaces.

Currently nouveau breaks this setup, as when acpi_video_backlight_support()
returns true, it does not register itself, resulting in no backlight control
at all.

This is esp. going to be a problem with 3.16 which will default to
video.use_native_backlight=1, and thus nouveau based laptops with a win8 bios
will get no backlight control at all.

This also likely explains why the previous attempt to make
video.use_native_backlight=1 the default was not a success, as without this
patch having a default of video.use_native_backlight=1 will cause regressions.

Note this effectively reverts commit 5bead799d3f8 (drm/nouveau: don't
expose backlight control when available through ACPI).

References: https://bugzilla.redhat.com/show_bug.cgi?id=1093171
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drm/sysfs: sort out minor and connector device object lifetimes.

So drm was abusing device lifetimes, by having embedded device structures
in the minor and connector it meant that the lifetime of the internal drm
objects (drm_minor and drm_connector) were tied to the lifetime of the device
files in sysfs, so if something kept those files opened the current code
would kfree the objects and things would go downhill from there.

Now in reality there is no need for these lifetimes to be so intertwined,
especailly with hotplugging of devices where we wish to remove the sysfs
and userspace facing pieces before we can unwind the internal objects due
to open userspace files or mmaps, so split the objects out so the struct
device is no longer embedded and do what fbdev does and just allocate
and remove the sysfs inodes separately.

Signed-off-by: Dave Airlie <airlied@redhat.com>

drm/nouveau/drm: adding support for backlight control of GT525M (NVC0)

This patch adds support for the backlight control of the NVIDIA GT
525M, which identifies itself as a member of the NVC0 family.

v2. Extended to handle Kepler too

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau: handle backlight_device_register failure

Found by smatch.

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau: port remainder of drm code, and rip out compat layer

v2: Ben Skeggs <bskeggs@redhat.com>
- fill in nouveau_pm.dev to prevent oops
- fix ppc issues (build + OF shadow)

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau/backlight: remove dependence on nouveau_drv.h

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau: implement devinit subdev, and new init table parser

v2:
- make sure not to execute display scripts unless resuming

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau: implement module init functions in nouveau_drm.c

These currently just call the existing ones in nouveau_drv.c, but will be
extended in upcoming commits. This needed to be separated from the current
code as there will be some header clashes until things are ported.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

UAPI: (Scripted) Convert #include "..." to #include <path/...> in drivers/gpu/

Convert #include "..." to #include <path/...> in drivers/gpu/.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>

drm/nva3/backlight: add suppport for newer style backlight regs

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nv50/backlight: express brightness level in percent

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nv50/backlight: take the sor into account when bashing regs

I'm sure that out there somewhere, someone will need this. We currently
haven't seen an example of LVDS being on a non-0 SOR so far though.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drm/nouveau/backlight: make more consistent with rest of driver style

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

nouveau: change the backlight parent device to the connector, not the PCI dev

We may eventually end up with per-connector backlights, especially with
ddcci devices. Make sure that the parent node for the backlight device is
the connector rather than the PCI device.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: David Airlie <airlied@linux.ie>
Cc: Alex Deucher <alexdeucher@gmail.com>
Acked-by: Ben Skeggs <bskeggs@redhat.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: Sedat Dilek <sedat.dilek@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

backlight: add backlight type

There may be multiple ways of controlling the backlight on a given
machine. Allow drivers to expose the type of interface they are
providing, making it possible for userspace to make appropriate policy
decisions.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: David Airlie <airlied@linux.ie>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drm/nouveau: don't expose backlight control when available through ACPI

Avoid confusing userspace by not publishing backlight controls if ACPI
equivalents are available.

Reported-by: Aaron Sowry <aaron@aeneby.se>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

backlight: constify backlight_ops

backlight_device_register has been expecting a const "ops" argument, and using
it as such, since 9905a43b2d563e6f89e4c63c4278ada03f2ebb14. Let's make the
remaining backlight_ops instances const.

Inspired by hunks of the grsecurity patch, updated for newer kernels.

Signed-off-by: Lionel Debroux <lionel_debroux@yahoo.fr>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

backlight: Allow properties to be passed at registration

Values such as max_brightness should be set before backlights are
registered, but the current API doesn't allow that. Add a parameter to
backlight_device_register and update drivers to ensure that they
set this correctly.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

drm/nouveau: Add DRM driver for NVIDIA GPUs

This adds a drm/kms staging non-API stable driver for GPUs from NVIDIA.

This driver is a KMS-based driver and requires a compatible nouveau
userspace libdrm and nouveau X.org driver.

This driver requires firmware files not available in this kernel tree,
interested parties can find them via the nouveau project git archive.

This driver is reverse engineered, and is in no way supported by nVidia.

Support for nearly the complete range of nvidia hw from nv04->g80 (nv50)
is available, and the kms driver should support driving nearly all
output types (displayport is under development still) along with supporting
suspend/resume.

This work is all from the upstream nouveau project found at
nouveau.freedesktop.org.

The original authors list from nouveau git tree is:
Anssi Hannula <anssi.hannula@iki.fi>
Ben Skeggs <bskeggs@redhat.com>
Francisco Jerez <currojerez@riseup.net>
Maarten Maathuis <madman2003@gmail.com>
Marcin Kościelnicki <koriakin@0x04.net>
Matthew Garrett <mjg@redhat.com>
Matt Parnell <mparnell@gmail.com>
Patrice Mandin <patmandin@gmail.com>
Pekka Paalanen <pq@iki.fi>
Xavier Chantry <shiningxc@gmail.com>
along with project founder Stephane Marchesin <marchesin@icps.u-strasbg.fr>

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>