The OLS value is now obsolete. Exactly the same value is guarateed to be always
available as PLR->seqno. Thus it is safe to remove the OLS completely. And also
to rename the PLR to OLR to keep the 'outstanding lazy ...' naming convention
valid.

For: VIZ-4377
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NThomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Added reference counting of the request structure around __wait_seqno() calls.
This is a precursor to updating the wait code itself to take the request rather
than a seqno. At that point, it would be a Bad Idea for a request object to be
retired and freed while the wait code is still using it.

v3:

Note that even though the mutex lock is held during a call to i915_wait_seqno(),
it is still necessary to explicitly bump the reference count. It appears that
the shrinker can asynchronously retire items even though the mutex is locked.

For: VIZ-4377
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NThomas Daniel <Thomas.Daniel@intel.com>
[danvet: Remove wrongly squashed hunk which breaks the build.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Convert the throttle code to use the request structure rather than extracting a
ring/seqno pair from it and using those. This is in preparation for
__wait_seqno() becoming __wait_request().

For: VIZ-4377
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NThomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The object structure contains the last read, write and fenced seqno values for
use in syncrhonisation operations. These have now been replaced with their
request structure counterparts.

Note that to ensure that objects do not end up with dangling pointers, the
assignments of last_*_req include reference count updates. Thus a request cannot
be freed if an object is still hanging on to it for any reason.

v2: Corrected 'last_rendering_' to 'last_read_' in a number of comments that did
not get updated when 'last_rendering_seqno' became 'last_read|write_seqno'
several millenia ago.

For: VIZ-4377
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NThomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Added helper functions for retrieving the ring and seqno entries from a request
structure. This allows the internal workings of the request structure to be
hidden from code that is using these. It also allows for useful
workarounds/debug code to be added as or when necessary.

Note that it is intended that the majority (if not all) uses of the seqno
accessor will disappear eventually as code is updated to use the request
structure itself rather than working with seqno values.

For: VIZ-4377
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NThomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The plan is to use request structures everywhere that seqno values were
previously used. This means saving pointers to structures in places that used to
be simple integers. In turn, that means that the target structure now needs much
more stringent lifetime tracking. That is, it must not be freed while some other
random object still holds a pointer to it.

To achieve this tracking, a reference count needs to be added. Whenever a
pointer to the structure is saved away, the count must be incremented and the
free must only occur when all references have been released.

For: VIZ-4377
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NThomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The aim is to replace seqno values with request structures. A step along the way
is to switch to using the PLR in preference to the OLS. That requires the PLR to
only be valid when and only when the OLS is also valid. I.e., the two must be
kept in lock step. Then, code which was using the OLS can be safely switched
over to using the PLR instead.

For: VIZ-4377
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Reviewed-by: NThomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

That's the version actually taking the dev_priv->power_domains lock.
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Before suspending, we wait upon the outstanding GPU requests and flush
our pending idle handlers. This should downclock the GPU to its lowest
power state. Add a WARN to check that the delayed tasks were run and did
their job properly.
Suggested-by: NAkash Goel <akash.goel@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now unused.
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

The logical ring code was updating the software ring 'head' value
by reading the hardware 'HEAD' register. In LRC mode, this is not
valid as the hardware is not necessarily executing the same context
that is being processed by the software. Thus reading the h/w HEAD
could put an unrelated (undefined, effectively random) value into
the s/w 'head' -- A Bad Thing for the free space calculations.
Signed-off-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NDeepak S <deepak.s@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The request queue is per-engine, and may therefore contain requests
from several different contexts/ringbuffers. In determining which
request to wait for, this function should only consider requests
from the ringbuffer that it's checking for space, and ignore any
that it finds that belong to other contexts.
Signed-off-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NDeepak S <deepak.s@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This patch is the last in series of VLV/CHV PSR,
that finally enable PSR by adding it to HAS_PSR
and calling the proper enable and disable
functions on the right places.

Although it is still disabled by default.

v2: Rebase over intel_psr and merge Durgadoss's fixes.
v3: Fix typo.
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NDurgadoss R <durgadoss.r@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Add debugfs support for Valleyview and Cherryview considering that
we have PSR per pipe and  we don't have any kind of
performance counter as we have on other platforms that support PSR.
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NDurgadoss R <durgadoss.r@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This patch introduces exit/activate functions for PSR
on VLV+. Since on VLV+ HW cannot track frame updates and force PSR
exit let's use fully SW tracking available.

v2: Rebase over intel_psr.c;
    Remove Single Frame update transitioning from state 3 to 5 directly;
    Fake a software invalidation for sprites and cursor so we don't miss
    any screen update;

v3: As pointed out by Durgadoss msecs_to_jiffies used on wait_for only uses int,
    so let's use 1 instead. Althought the 1/4 of this is needed for the
    transition let's use 1 for simplicity;
    Also fix comments as suggested by Durgadoss

Cc: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NDurgadoss R <durgadoss.r@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The biggest difference from HSW/BDW PSR here is that VLV enable_source
function enables PSR but let it in Inactive state. So it might be called
on early stage along with setup and enable_sink ones.

v2: Rebase over intel_psr.c;
    Remove docs from static functions;
    Merge vlv_psr_active_on_pipe;
    Timeout for psr transition is 250us;
    Remove SRC_TRASMITTER_STATE;

v3: Rebase after is_psr_enabled function got removed;
    Get SRC_TRANSMITTER_STATE back to be on the safe side since
    default for panels is to require link training on exit when
    main link off;
    As pointed out by Durgadoss msecs_to_jiffies used on wait_for only uses int,
    so let's use 1 instead. Althought the 1/4 of this is needed for the
    transition let's use 1 for simplicity;

Cc: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NDurgadoss R <durgadoss.r@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Baytrail (Valleyview) and Braswell (Cherryview) uses a complete different
implementation of PSR that we currently have supported for
Haswell and Broadwell. So let's start by adding registers definitions.

I usually don't like commit that adds just registers without using,
but after I put all in one commit I realized that no one would want
to take the AR to review it so I decided to split in order to make
reviewer's life easier. Only last commit in this series will actually
enable the PSR on intel enable panel path.

But as it happens currently with HSW/BDW the plan is to let it
disabled by default (protected by kernel parameter)
while we are able to fully validate it.

v2: Remove a unused bit definition that isn't used on vlv and
    reserved on chv as pointed out by Durgadoss.

Cc: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NDurgadoss R <durgadoss.r@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This function was in use to check if PSR feature got enabled.
However on HSW and BDW we currently force psr exit by disabling
EDP_PSR_ENABLE bit at EDP_PSR_CTL(dev). So this function was actually
returning the active/inactive state that is different from the enable/disable
meaning and had the risk of false negative.

But anyway this check with DRRS was dangerous, since DRRS could try to get enabled
before PSR gets there. So let's just remove it for now.
A proper synchronization mechanism must be implemented later probably
using pipe config.

Cc: Daniel Vetter <daniel@ffwll.ch>
Reviewed-by: NDurgadoss R <durgadoss.r@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Single frame update is a feature available on BDW for PSR that allows
Source to send Sink only one frame and get it updated. Usually useful
when page flipping. However with our frontbuffer tracking where we force
psr exit on flips we don't need this feature.

Also after it got added here many workaround was added to documentation
to mask some bits when using single frame update. So the safest thing
is to just stop using it.

v2: Rebase after removing skip aux one and fixing typo on commit message.
Reviewed-by: NDurgadoss R <durgadoss.r@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

OEMs can specify if full_link might be always enabled, i.e. only_standby
over VBT.
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NDurgadoss R <durgadoss.r@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Let's use VBT + 1 now we parse it.

v2: fix subject

v3: rebase over intel_psr and without counting on previous fix

Cc: Arthur Runyan <arthur.j.runyan@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NDurgadoss R <durgadoss.r@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

PSR (aka SRD) block is defined at VBT and currently being used.
Mainly/At-least to configure the amount of idle_frames require to get
back to PSR Entry.
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NDurgadoss R <durgadoss.r@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Because the plane registers are different in Skylake we need to adapt
the MMIO code as well.

v2: Don't introduce yet another vfunc when the direction is do
consolidate the plane updates to use the same code path (Daniel)

v3:
  - Use enum pipe instead of int (Ville)
  - Also update PLANE_STRIDE when the tiling has changed (Ville)
  - Put intel_mark_page_flip_active() in the shared code (Damien)

v4:
  - Remove unused variable

v5:
  - Fix whitespace Vs tabs (Ville)
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

v2: Put the DPLL0 state readout in skylake_get_ddi_pll(), closer to
where the PLL assignement read out is done rather than the frequency
readout function. (Daniel)

v3: Remove stray new line (Damien)
    Add Paulo's r-b tag for v1

Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com> (v1)
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On pre-HSW we have two encoders per digital port: one HDMI, one DP.
However they are the same physical port in hardware and we can't enable
both at the same time. Reject the modeset if the user attempts this.

So far we've been saved by the fact that we never see both HDMI and DP
connectors as connected. But if the user decides to force a mode anyway,
all kinds of funny stuff might happen.

Unfortunately we don't seem to have any way to inform userspace that
such configurations are invalid except by returning an error from
setcrtc. possible_clones only covers real cloning situations, and
looking at the connector names doesn't work either since we don't
always register both connectors for the same port. I suppose the
only way to fix that would be to expose only a single encoder per
digital port like we do on HSW+ but that would be a fairly large
undertaking for little gain.

kms_setmode hits this since it forces modes on non-connected VGA and
HDMI connectors. Previosuly it just resulted in weirdness such as
failed link training. With this patch it will now get an error back
from the kernel and will die with an assert since it thinks that the
configuration should be fine.

v2: Deal with INTEL_OUTPUT_UNKNOWN (Paulo)

Cc: Paulo Zanoni <przanoni@gmail.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Atm, igt/gem_reset_stats can trigger the recently added WARN on
left-over PM_IIR bits in gen6_enable_rps_interrupts(). There are two
reasons for this:
1. we call intel_enable_gt_powersave() without a preceeding
   intel_disable_gt_powersave()
2. gen6_disable_rps_interrupts() doesn't mask interrupts in PM_IMR

1. means RPS interrupts will remain enabled and can be serviced during
the HW initialization after a GPU reset. 2. means even if we called
gen6_disable_rps_interrupts() any new RPS interrupt during RPS
initialization would still propagate to PM_IIR too early (though
wouldn't be serviced).

This patch solves the 2. issue by also masking interrupts in PM_IMR, the
following patch fixes 1. getting rid of the WARN. This also makes
intel_enable_gt_powersave() and intel_disable_gt_powersave() more
symmetric.

Since gen6_disable_rps_interrupts() is called during driver loading with
i915 interrupts disabled add a new version of gen6_disable_pm_irq() that
doesn't WARN for this.

Also while at it, get the irq_lock around the whole PM_IMR/IER/IIR
programming sequence and make sure that any queued PM_IIR bit is also
cleared.

The WARN was caught by PRTS after I sent my previous RPS sanitizing
patchset and I could easily reproduce it on HSW. To actually fix it we
also need the next patch.
Reported-by: NHe, Shuang <shuang.he@intel.com>
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We don't really synchronously turn them off from debugfs. We try to
avoid hitting them too badly by waiting one vblank, but apparently the
irq handler can still race through that gap.

Since this isn't really all that important for testcases, only for
debugging CRC issues let's tune it down to a debug message.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=82602
Cc: Damien Lespiau <damien.lespiau@intel.com>
Acked-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

Dynamic context pinning for LRCs introduced a leak in legacy mode.
Reinstate context unreference in i915_gem_free_request for legacy contexts.

Leak reported by i-g-t/drv_module_reload fixed by this patch.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=86507Signed-off-by: NThomas Daniel <thomas.daniel@intel.com>
Reviewed-by: John Harrison<John.C.Harrison@Intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Updates in forcewake range for Render/Media/Common
power wells for Gen9.
Signed-off-by: NAkash Goel <akash.goel@intel.com>
Signed-off-by: NZhe Wang <zhe1.wang@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Before testing if the panel VDD is enabled on eDP cancel any pending
disable worker. This makes sure the worker will be triggered with a
delay from the last time edp_panel_vdd_schedule_off() is called, not
the first time. This avoids unnecessary overhead.

https://bugs.freedesktop.org/show_bug.cgi?id=86201

v2: use cancel_delayed_work() instead of cancel_delayed_work_sync()
as the pps_mutexes will provide the required serialization with
edp_panel_vdd_work() while the sync variant may deadlock. Suggested
by Ville Syrjälä <ville.syrjala@linux.intel.com>.
Made commit message a bit clearer.
Signed-off-by: NEgbert Eich <eich@suse.de>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The crc code doesn't handle anything really that could drop the
register state (by design so that we have less complexity). Which
means userspace may only start crc capture once the pipe is fully set
up.

With an i-g-t patch this will be the case, but there's still the
problem that this results in obscure unclaimed register write
failures. Which is a pain to debug.

So instead make sure we don't have the basic unclaimed register write
failure by grabbing runtime pm references. And reject completely
invalid requests with -EIO. This is still racy of course, but for a
test library we don't really care - if userspace shuts down the pipe
right afterwards the entire setup will be lost anyway.

v2: Put instead of get, spotted by Damien. Also explain the runtime pm
dance.

v3: There's really no need for rpm get/put since power_is_enabled only
checks software state (Damien).

References: https://bugs.freedesktop.org/show_bug.cgi?id=86092
Cc: Damien Lespiau <damien.lespiau@intel.com> (v2)
Tested-by: Nlu hua <huax.lu@intel.com>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

The GPU reset also resets the display on gen3/4. The g33 docs say we
should disable all planes before flipping the reset switch. Just
disable all the crtcs instead. That seems a nicer thing to do anyway.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On gen4 and earlier the GPU reset also resets the display, so we should
protect against concurrent modeset operations. Grab all the modeset locks
around the entire GPU reset dance, remebering first ti dislogde any
pending page flip to make sure we don't deadlock. Any pageflip coming
in between these two steps should fail anyway due to reset_in_progress,
so this should be safe.

This fixes a lot of failed asserts in the modeset code when there's a
modeset racing with the reset. Naturally the asserts aren't happy when
the expected state has disappeared.

v2: Drop UMS checks, complete pending flips after the reset (Daniel)

Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

g33 seems to sit somewhere between the 915/945/965 style and the
g4x style. The bits look like g4x, but we still need to do a full
reset including display.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

915/945 have the same reset registers as 965, so share the code.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On pre-ctg GPU reset also resets the display hardware. Force a mode
restore after the GPU reset, and also re-init clock gating.

v2: Use intel_modeset_init_hw() instead of intel_init_clock_gating()
    in case more relevant stuff gets added there at some point
    Restore interrupts after the reset as well
Tested-by: NKenneth Graunke <kenneth@whitecape.org>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On pre-ctg the reset bit directly controls the reset signal. We must
assert it for >=20usec and then deassert it. Bit 1 is a RO status bit
which should also go down when the reset is no longer asserted.
Tested-by: NKenneth Graunke <kenneth@whitecape.org>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

There's quite a few bug reports with error states where the error
reasons makes just about no sense at all. Like dying on tlbs for a
display plane that's not even there. Also users don't really report a
lot of bad side effects generally, just the error states.

Furthermore we don't even enable these interrupts any more on gen5+
(though the handling code is still there). So this mostly concerns old
platforms.

Given all that lets make our lives a bit easier and stop capturing
error states, in the hopes that we can just ignore them. In case
that's not true and the gpu indeed dies the hangcheck should
eventually kick in. And I've left some debug log in to make this case
noticeble. Referenced bug is just an example.

v2: Fix missing \n Jani spotted.

References: https://bugs.freedesktop.org/show_bug.cgi?id=82095
References: https://bugs.freedesktop.org/show_bug.cgi?id=85944Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The problem here is that SNA pins batchbuffers to etch out a bit more
performance. Iirc it started out as a w/a for i830M (which we've
implemented in the kernel since a long time already). The problem is
that the pin ioctl wasn't added in

commit d23db88c
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri May 23 08:48:08 2014 +0200

    drm/i915: Prevent negative relocation deltas from wrapping

Fix this by simply disallowing pinning from userspace so that the
kernel is in full control of batch placement again. Especially since
distros are moving towards running X as non-root, so most users won't
even be able to see any benefits.

UMS support is dead now, but we need this minimal patch for
backporting. Follow-up patch will remove the pin ioctl code
completely.

Note to backporters: You must have both

commit b45305fc
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Mon Dec 17 16:21:27 2012 +0100

    drm/i915: Implement workaround for broken CS tlb on i830/845

which laned in 3.8 and

commit c4d69da1
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Mon Sep 8 14:25:41 2014 +0100

    drm/i915: Evict CS TLBs between batches

which is also marked cc: stable. Otherwise this could introduce a
regression by disabling the userspace w/a without the kernel w/a being
fully functional on i830/45.

References: https://bugs.freedesktop.org/show_bug.cgi?id=76554#c116
Cc: stable@vger.kernel.org # requires c4d69da1 and v3.8
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

In all likelihood we will do a few hundred errnoneous register
operations if we do a single invalid register access whilst the device
is suspended. As each instance causes a WARN, this floods the system
logs and can make the system unresponsive.

The warning was first introduced in
commit b2ec142c
Author: Paulo Zanoni <paulo.r.zanoni@intel.com>
Date:   Fri Feb 21 13:52:25 2014 -0300

    drm/i915: call assert_device_not_suspended at gen6_force_wake_work

and despite the claims the WARN is still encountered in the wild today.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>