drm/i915: add a dedicated workqueue inside drm_i915_private

In order to avoid flush_scheduled_work() usage, add a dedicated
workqueue in the drm_i915_private structure. In this way, we don't
need to use the system queue anymore.

This change is mostly mechanical and based on Tetsuo's original
patch[1].

v6 by Jani:
- Also create unordered_wq for mock device

Link: https://patchwork.freedesktop.org/series/114608/ [1]
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/c816ebe17ef08d363981942a096a586a7658a65e.1686231190.git.jani.nikula@intel.com

drm/i915: Never return 0 if not all requests retired

Users of intel_gt_retire_requests_timeout() expect 0 return value on
success. However, we have no protection from passing back 0 potentially
returned by a call to dma_fence_wait_timeout() when it succedes right
after its timeout has expired.

Replace 0 with -ETIME before potentially using the timeout value as return
code, so -ETIME is returned if there are still some requests not retired
after timeout, 0 otherwise.

v3: Use conditional expression, more compact but also better reflecting
intention standing behind the change.

v2: Move the added lines down so flush_submission() is not affected.

Fixes: f33a8a51602c ("drm/i915: Merge wait_for_timelines with retire_request")
Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Cc: stable@vger.kernel.org # v5.5+
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221121145655.75141-3-janusz.krzysztofik@linux.intel.com

drm/i915: Never return 0 if not all requests retired

Users of intel_gt_retire_requests_timeout() expect 0 return value on
success. However, we have no protection from passing back 0 potentially
returned by a call to dma_fence_wait_timeout() when it succedes right
after its timeout has expired.

Replace 0 with -ETIME before potentially using the timeout value as return
code, so -ETIME is returned if there are still some requests not retired
after timeout, 0 otherwise.

v3: Use conditional expression, more compact but also better reflecting
intention standing behind the change.

v2: Move the added lines down so flush_submission() is not affected.

Fixes: f33a8a51602c ("drm/i915: Merge wait_for_timelines with retire_request")
Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Cc: stable@vger.kernel.org # v5.5+
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221121145655.75141-3-janusz.krzysztofik@linux.intel.com
(cherry picked from commit f301a29f143760ce8d3d6b6a8436d45d3448cde6)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drm/i915: Never return 0 if not all requests retired

Users of intel_gt_retire_requests_timeout() expect 0 return value on
success. However, we have no protection from passing back 0 potentially
returned by a call to dma_fence_wait_timeout() when it succedes right
after its timeout has expired.

Replace 0 with -ETIME before potentially using the timeout value as return
code, so -ETIME is returned if there are still some requests not retired
after timeout, 0 otherwise.

v3: Use conditional expression, more compact but also better reflecting
intention standing behind the change.

v2: Move the added lines down so flush_submission() is not affected.

Fixes: f33a8a51602c ("drm/i915: Merge wait_for_timelines with retire_request")
Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Cc: stable@vger.kernel.org # v5.5+
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221121145655.75141-3-janusz.krzysztofik@linux.intel.com
(cherry picked from commit f301a29f143760ce8d3d6b6a8436d45d3448cde6)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

drm/i915/guc: Update intel_gt_wait_for_idle to work with GuC

When running the GuC the GPU can't be considered idle if the GuC still
has contexts pinned. As such, a call has been added in
intel_gt_wait_for_idle to idle the UC and in turn the GuC by waiting for
the number of unpinned contexts to go to zero.

v2: rtimeout -> remaining_timeout
v3: Drop unnecessary includes, guc_submission_busy_loop ->
guc_submission_send_busy_loop, drop negatie timeout trick, move a
refactor of guc_context_unpin to earlier path (John H)
v4: Add stddef.h back into intel_gt_requests.h, sort circuit idle
function if not in GuC submission mode

Cc: John Harrison <john.c.harrison@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210721215101.139794-16-matthew.brost@intel.com

drm/i915: Request watchdog infrastructure

Prepares the plumbing for setting request/fence expiration time. All code
is put in place but is never activated due yet missing ability to actually
configure the timer.

Outline of the basic operation:

A timer is started when request is ready for execution. If the request
completes (retires) before the timer fires, timer is cancelled and nothing
further happens.

If the timer fires request is added to a lockless list and worker queued.
Purpose of this is twofold: a) It allows request cancellation from a more
friendly context and b) coalesces multiple expirations into a single event
of consuming the list.

Worker locklessly consumes the list of expired requests and cancels them
all using previous added i915_request_cancel().

Associated timeout value is stored in rq->context.watchdog.timeout_us.

v2:
* Log expiration.

v3:
* Include more information about user timeline in the log message.

v4:
* Remove obsolete comment and fix formatting. (Matt)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210324121335.2307063-6-tvrtko.ursulin@linux.intel.com

drm/i915/gt: SPDX cleanup

Clean up the SPDX licence declarations to comply with checkpatch.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210122192913.4518-1-chris@chris-wilson.co.uk
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drm/i915/gt: Remove uninterruptible parameter from intel_gt_wait_for_idle

Now that the only user of the uninterruptible wait was eliminated,
remove the support.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201209164008.5487-3-chris@chris-wilson.co.uk

drm/i915/gem: Unpin idle contexts from kswapd reclaim

We removed retiring requests from the shrinker in order to decouple the
mutexes from reclaim in preparation for unravelling the struct_mutex.
The impact of not retiring is that we are much less agressive in making
global objects available for shrinking, as such objects remain pinned
until they are flushed by a heartbeat pulse following the last retired
request along their timeline. In order to ensure that pulse occurs in
time for memory reclamation, we should kick it from kswapd.

The catch is that we have added some flush_work() into the retirement
phase (to ensure that we reach a global idle in a timely manner), but
these flush_work() are not eligible (i.e do not belong to WQ_MEM_RELCAIM)
for use from inside kswapd. To avoid flushing those workqueues, we teach
the retirer not to do so unless we are actually waiting, and only do the
plain retire from inside the shrinker.

Note that for execlists, we already retire completed contexts as they
are scheduled out, so it should not be keeping global state
unnecessarily pinned. The legacy ringbuffer however...

References: 9e9539800dd4 ("drm/i915: Remove waiting & retiring from shrinker paths")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200708173748.32734-1-chris@chris-wilson.co.uk

drm/i915/gt: Check carefully for an idle engine in wait-for-idle

intel_gt_wait_for_idle() tries to wait until all the outstanding requests
are retired and the GPU is idle. As a side effect of retiring requests,
we may submit more work to flush any pm barriers, and so the
wait-for-idle tries to flush the background pm work and catch the new
requests. However, if the work completed in the background before we
were able to flush, it would queue the extra barrier request without us
noticing -- and so we would return from wait-for-idle with one request
remaining. (This breaks e.g. record_default_state where we need to wait
until that barrier is retired, and it may slow suspend down by causing
us to wait on the background retirement worker as opposed to immediately
retiring the barrier.)

However, since we track if there has been a submission since the engine
pm barrier, we can very quickly detect if the idle barrier is still
outstanding.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1763
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200423085940.28168-1-chris@chris-wilson.co.uk

drm/i915/gt: Move the late flush_submission in retire to the end

Avoid flushing the submission queue (of others) under the client's
timeline lock, but instead move it to the end so that we may catch more.

References: https://gitlab.freedesktop.org/drm/intel/-/issues/1066
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200420125356.26614-2-chris@chris-wilson.co.uk

drm/i915: Extend intel_wakeref to support delayed puts

In some cases we want to hold onto the wakeref for a little after the
last user so that we can avoid having to drop and then immediately
reacquire it. Allow the last user to specify if they would like to keep
the wakeref alive for a short hysteresis.

v2: Embrace bitfield.h for adjustable flags.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200323103221.14444-1-chris@chris-wilson.co.uk

drm/i915/gt: Drop the timeline->mutex as we wait for retirement

As we have pinned the timeline (using tl->active_count), we can safely
drop the tl->mutex as we wait for what we believe to be the final
request on that timeline. This is useful for ensuring that we do not
block the engine heartbeat by hogging the kernel_context's timeline on a
dead GPU.

References: https://gitlab.freedesktop.org/drm/intel/issues/1364
Fixes: 058179e72e09 ("drm/i915/gt: Replace hangcheck by heartbeats")
Fixes: f33a8a51602c ("drm/i915: Merge wait_for_timelines with retire_request")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200303140009.1494819-1-chris@chris-wilson.co.uk
(cherry picked from commit 82126e596d8519baac416aee83cad938f1d23cf8)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drm/i915/gt: Drop the timeline->mutex as we wait for retirement

As we have pinned the timeline (using tl->active_count), we can safely
drop the tl->mutex as we wait for what we believe to be the final
request on that timeline. This is useful for ensuring that we do not
block the engine heartbeat by hogging the kernel_context's timeline on a
dead GPU.

References: https://gitlab.freedesktop.org/drm/intel/issues/1364
Fixes: 058179e72e09 ("drm/i915/gt: Replace hangcheck by heartbeats")
Fixes: f33a8a51602c ("drm/i915: Merge wait_for_timelines with retire_request")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200303140009.1494819-1-chris@chris-wilson.co.uk

drm/i915/gt: Prevent queuing retire workers on the virtual engine

Virtual engines are fleeting. They carry a reference count and may be freed
when their last request is retired. This makes them unsuitable for the
task of housing engine->retire.work so assert that it is not used.

Tvrtko tracked down an instance where we did indeed violate this rule.
In virtual_submit_request, we flush a completed request directly with
__i915_request_submit and this causes us to queue that request on the
veng's breadcrumb list and signal it. Leading us down a path where we
should not attach the retire.

Reported-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: dc93c9b69315 ("drm/i915/gt: Schedule request retirement when signaler idles")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200206204915.2636606-1-chris@chris-wilson.co.uk
(cherry picked from commit f91d8156ab8afb32447cd2bf3189219bab943f18)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

drm/i915/gt: Prevent queuing retire workers on the virtual engine

Virtual engines are fleeting. They carry a reference count and may be freed
when their last request is retired. This makes them unsuitable for the
task of housing engine->retire.work so assert that it is not used.

Tvrtko tracked down an instance where we did indeed violate this rule.
In virtual_submit_request, we flush a completed request directly with
__i915_request_submit and this causes us to queue that request on the
veng's breadcrumb list and signal it. Leading us down a path where we
should not attach the retire.

Reported-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: dc93c9b69315 ("drm/i915/gt: Schedule request retirement when signaler idles")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200206204915.2636606-1-chris@chris-wilson.co.uk

drm/i915/gt: Flush ongoing retires during wait_for_idle

Synchronise with any background retires and parking we may have spawned,
so that all requests are accounted for.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/878
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200102231604.1669010-1-chris@chris-wilson.co.uk

drm/i915/gt: Flush other retirees inside intel_gt_retire_requests()

Our goal in wait_for_idle (intel_gt_retire_requests) is to the current
workload *and* their idle barriers. This requires us to notice the late
arrival of those, which is done by inspecting the list of active
timelines. However, if a concurrent retirer is running that new timeline
may not be added until after we drop the lock -- so flush concurrent
retirers before we take the lock and inspect the list.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/878
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191223211008.2371613-1-chris@chris-wilson.co.uk

drm/i915/gt: Tidy up checking active timelines during retirement

Use the status of the timeline request list as we retire it to determine
if the timeline is still active.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Acked-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191223150833.2329366-1-chris@chris-wilson.co.uk

drm/i915/gt: Repeat wait_for_idle for retirement workers

Since we may retire timelines from secondary workers,
intel_gt_retire_requests() is not always a reliable indicator that all
pending retirements are complete. If we do detect secondary workers are
in progress, recommend intel_gt_wait_for_idle() to repeat the retirement
check.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191221180204.1201217-1-chris@chris-wilson.co.uk

drm/i915: Remove i915->kernel_context

Allocate only an internal intel_context for the kernel_context, forgoing
a global GEM context for internal use as we only require a separate
address space (for our own protection).

Now having weaned GT from requiring ce->gem_context, we can stop
referencing it entirely. This also means we no longer have to create random
and unnecessary GEM contexts for internal use.

GEM contexts are now entirely for tracking GEM clients, and intel_context
the execution environment on the GPU.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Acked-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191221160324.1073045-1-chris@chris-wilson.co.uk

drm/i915/gt: Schedule request retirement when signaler idles

Very similar to commit 4f88f8747fa4 ("drm/i915/gt: Schedule request
retirement when timeline idles"), but this time instead of coupling into
the execlists CS event interrupt, we couple into the breadcrumb
interrupt and queue a timeline's retirement when the last signaler is
completed. This should allow us to more rapidly park ringbuffer
submission, and so help reduce power consumption on older systems.

v2: Fixup intel_engine_add_retire() to handle concurrent callers

References: 4f88f8747fa4 ("drm/i915/gt: Schedule request retirement when timeline idles")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191219124353.8607-1-chris@chris-wilson.co.uk

drm/i915/gt: Schedule request retirement when timeline idles

The major drawback of commit 7e34f4e4aad3 ("drm/i915/gen8+: Add RC6 CTX
corruption WA") is that it disables RC6 while Skylake (and friends) is
active, and we do not consider the GPU idle until all outstanding
requests have been retired and the engine switched over to the kernel
context. If userspace is idle, this task falls onto our background idle
worker, which only runs roughly once a second, meaning that userspace has
to have been idle for a couple of seconds before we enable RC6 again.
Naturally, this causes us to consume considerably more energy than
before as powersaving is effectively disabled while a display server
(here's looking at you Xorg) is running.

As execlists will get a completion event as each context is completed,
we can use this interrupt to queue a retire worker bound to this engine
to cleanup idle timelines. We will then immediately notice the idle
engine (without userspace intervention or the aid of the background
retire worker) and start parking the GPU. Thus during light workloads,
we will do much more work to idle the GPU faster... Hopefully with
commensurate power saving!

v2: Watch context completions and only look at those local to the engine
when retiring to reduce the amount of excess work we perform.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=112315
References: 7e34f4e4aad3 ("drm/i915/gen8+: Add RC6 CTX corruption WA")
References: 2248a28384fe ("drm/i915/gen8+: Add RC6 CTX corruption WA")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191125105858.1718307-3-chris@chris-wilson.co.uk
(cherry picked from commit 4f88f8747fa43c97c3b3712d8d87295ea757cc51)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drm/i915/gt: Close race between engine_park and intel_gt_retire_requests

The general concept was that intel_timeline.active_count was locked by
the intel_timeline.mutex. The exception was for power management, where
the engine->kernel_context->timeline could be manipulated under the
global wakeref.mutex.

This was quite solid, as we always manipulated the timeline only while
we held an engine wakeref.

And then we started retiring requests outside of struct_mutex, only
using the timelines.active_list and the timeline->mutex. There we
started manipulating intel_timeline.active_count outside of an engine
wakeref, and so introduced a race between __engine_park() and
intel_gt_retire_requests(), a race that could result in the
engine->kernel_context not being added to the active timelines and so
losing requests, which caused us to keep the system permanently powered
up [and unloadable].

The race would be easy to close if we could take the engine wakeref for
the timeline before we retire -- except timelines are not bound to any
engine and so we would need to keep all active engines awake. The
alternative is to guard intel_timeline_enter/intel_timeline_exit for use
outside of the timeline->mutex.

Fixes: e5dadff4b093 ("drm/i915: Protect request retirement with timeline->mutex")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191120165514.3955081-1-chris@chris-wilson.co.uk
(cherry picked from commit a6edbca74b305adc165e67065d7ee766006e6a48)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drm/i915/gt: Schedule request retirement when timeline idles

The major drawback of commit 7e34f4e4aad3 ("drm/i915/gen8+: Add RC6 CTX
corruption WA") is that it disables RC6 while Skylake (and friends) is
active, and we do not consider the GPU idle until all outstanding
requests have been retired and the engine switched over to the kernel
context. If userspace is idle, this task falls onto our background idle
worker, which only runs roughly once a second, meaning that userspace has
to have been idle for a couple of seconds before we enable RC6 again.
Naturally, this causes us to consume considerably more energy than
before as powersaving is effectively disabled while a display server
(here's looking at you Xorg) is running.

As execlists will get a completion event as each context is completed,
we can use this interrupt to queue a retire worker bound to this engine
to cleanup idle timelines. We will then immediately notice the idle
engine (without userspace intervention or the aid of the background
retire worker) and start parking the GPU. Thus during light workloads,
we will do much more work to idle the GPU faster... Hopefully with
commensurate power saving!

v2: Watch context completions and only look at those local to the engine
when retiring to reduce the amount of excess work we perform.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=112315
References: 7e34f4e4aad3 ("drm/i915/gen8+: Add RC6 CTX corruption WA")
References: 2248a28384fe ("drm/i915/gen8+: Add RC6 CTX corruption WA")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191125105858.1718307-3-chris@chris-wilson.co.uk

Revert "drm/i915/gt: Wait for new requests in intel_gt_retire_requests()"

From inside an active timeline in the execbuf ioctl, we may try to
reclaim some space in the GGTT. We need GGTT space for all objects on
!full-ppgtt platforms, and for context images everywhere. However, to
free up space in the GGTT we may need to remove some pinned objects
(e.g. context images) that require flushing the idle barriers to remove.
For this we use the big hammer of intel_gt_wait_for_idle()

However, commit 7936a22dd466 ("drm/i915/gt: Wait for new requests in
intel_gt_retire_requests()") will continue spinning on the wait if a
timeline is active but lacks requests, as is the case during execbuf
reservation. Spinning forever is quite time consuming, so revert that
commit and start again.

In practice, the effect commit 7936a22dd466 was trying to achieve is
accomplished by commit 1683d24c1470 ("drm/i915/gt: Move new timelines
to the end of active_list"), so there is no immediate rush to replace
the looping.

Testcase: igt/gem_exec_reloc/basic-range
Fixes: a46bfdc83fee ("drm/i915/gt: Wait for new requests in intel_gt_retire_requests()")
References: 1683d24c1470 ("drm/i915/gt: Move new timelines to the end of active_list")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191121071044.97798-1-chris@chris-wilson.co.uk
(cherry picked from commit 689122dcc36e08f53732adf7ae0246f62eff3eb6)
[Joonas: Corrected Fixes: tag ref to match drm-intel-next-fixes]
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

Revert "drm/i915/gt: Wait for new requests in intel_gt_retire_requests()"

From inside an active timeline in the execbuf ioctl, we may try to
reclaim some space in the GGTT. We need GGTT space for all objects on
!full-ppgtt platforms, and for context images everywhere. However, to
free up space in the GGTT we may need to remove some pinned objects
(e.g. context images) that require flushing the idle barriers to remove.
For this we use the big hammer of intel_gt_wait_for_idle()

However, commit 7936a22dd466 ("drm/i915/gt: Wait for new requests in
intel_gt_retire_requests()") will continue spinning on the wait if a
timeline is active but lacks requests, as is the case during execbuf
reservation. Spinning forever is quite time consuming, so revert that
commit and start again.

In practice, the effect commit 7936a22dd466 was trying to achieve is
accomplished by commit 1683d24c1470 ("drm/i915/gt: Move new timelines
to the end of active_list"), so there is no immediate rush to replace
the looping.

Testcase: igt/gem_exec_reloc/basic-range
Fixes: 7936a22dd466 ("drm/i915/gt: Wait for new requests in intel_gt_retire_requests()")
References: 1683d24c1470 ("drm/i915/gt: Move new timelines to the end of active_list")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191121071044.97798-1-chris@chris-wilson.co.uk

drm/i915/gt: Declare timeline.lock to be irq-free

Now that we never allow the intel_wakeref callbacks to be invoked from
interrupt context, we do not need the irqsafe spinlock for the timeline.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191120170858.3965380-1-chris@chris-wilson.co.uk

drm/i915/gt: Close race between engine_park and intel_gt_retire_requests

The general concept was that intel_timeline.active_count was locked by
the intel_timeline.mutex. The exception was for power management, where
the engine->kernel_context->timeline could be manipulated under the
global wakeref.mutex.

This was quite solid, as we always manipulated the timeline only while
we held an engine wakeref.

And then we started retiring requests outside of struct_mutex, only
using the timelines.active_list and the timeline->mutex. There we
started manipulating intel_timeline.active_count outside of an engine
wakeref, and so introduced a race between __engine_park() and
intel_gt_retire_requests(), a race that could result in the
engine->kernel_context not being added to the active timelines and so
losing requests, which caused us to keep the system permanently powered
up [and unloadable].

The race would be easy to close if we could take the engine wakeref for
the timeline before we retire -- except timelines are not bound to any
engine and so we would need to keep all active engines awake. The
alternative is to guard intel_timeline_enter/intel_timeline_exit for use
outside of the timeline->mutex.

Fixes: e5dadff4b093 ("drm/i915: Protect request retirement with timeline->mutex")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191120165514.3955081-1-chris@chris-wilson.co.uk

drm/i915/gt: Schedule next retirement worker first

As we may park the gt during request retirement, we may cancel the
retirement worker only to then program the delayed worker once more.

If we schedule the next delayed retirement worker first, if we then park
the gt, the work will remain cancelled.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191119162559.3313003-2-chris@chris-wilson.co.uk

drm/i915/gt: Wait for new requests in intel_gt_retire_requests()

Our callers fall into two categories, those passing timeout=0 who just
want to flush request retirements and those passing a timeout that need
to wait for submission completion (e.g. intel_gt_wait_for_idle()).
Currently, we only wait for a snapshot of timelines at the start of the
wait (but there was an expectation that new requests would cause timelines
to appear at the end). However, our callers, such as
intel_gt_wait_for_idle() before suspend, do require us to wait for the
power management requests emitted by retirement as well. If we don't,
then it takes an extra second or two for the background worker to flush
the queue and mark the GT as idle.

Fixes: 7e8057626640 ("drm/i915: Drop struct_mutex from around i915_retire_requests()")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191114225736.616885-1-chris@chris-wilson.co.uk
(cherry picked from commit 7936a22dd4660d24b4ca0668c02b0372127cab44)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drm/i915/gt: Flush retire.work timer object on unload

We need to wait until the timer object is marked as deactivated before
unloading, so follow up our gentle cancel_delayed_work() with the
synchronous variant to ensure it is flushed off a remote cpu before we
mark the memory as freed.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111994
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191115150841.880349-1-chris@chris-wilson.co.uk

drm/i915/gt: Wait for new requests in intel_gt_retire_requests()

Our callers fall into two categories, those passing timeout=0 who just
want to flush request retirements and those passing a timeout that need
to wait for submission completion (e.g. intel_gt_wait_for_idle()).
Currently, we only wait for a snapshot of timelines at the start of the
wait (but there was an expectation that new requests would cause timelines
to appear at the end). However, our callers, such as
intel_gt_wait_for_idle() before suspend, do require us to wait for the
power management requests emitted by retirement as well. If we don't,
then it takes an extra second or two for the background worker to flush
the queue and mark the GT as idle.

Fixes: 7e8057626640 ("drm/i915: Drop struct_mutex from around i915_retire_requests()")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191114225736.616885-1-chris@chris-wilson.co.uk

drm/i915: Pass in intel_gt at some for_each_engine sites

Where the function, or code segment, operates on intel_gt, we need to
start passing it instead of i915 to for_each_engine(_masked).

This is another partial step in migration of i915->engines[] to
gt->engines[].

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191017094500.21831-2-tvrtko.ursulin@linux.intel.com

drm/i915/gt: Flush submission tasklet before waiting/retiring

A common bane of ours is arbitrary delays in ksoftirqd processing our
submission tasklet. Give the submission tasklet a kick before we wait to
avoid those delays eating into a tight timeout.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Stuart Summers <stuart.summers@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191008105655.13256-1-chris@chris-wilson.co.uk

drm/i915/gt: Treat a busy timeline as 'active' while waiting

If we cannot claim the timeline->mutex while preparing for a wait on it,
we have to skip the timeline. In doing so, treat it as active so that
under a intel_gt_wait_for_idle() loop, we repeat the wait after
scheduling away.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191006165002.30312-4-chris@chris-wilson.co.uk

drm/i915/gt: Restore dropped 'interruptible' flag

Lost in the rebasing was Tvrtko's reminder that we need to keep an
uninterruptible wait around for the Ironlake VT-d w/a

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191006165002.30312-3-chris@chris-wilson.co.uk

drm/i915: Move request runtime management onto gt

Requests are run from the gt and are tided into the gt runtime power
management, so pull the runtime request management under gt/

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-12-chris@chris-wilson.co.uk