[Intel-gfx] [PATCH] drm/i915/hsw: Fix GPU hang during resume from S3-devices state

[Chris Wilson]

On Wed, Oct 12, 2016 at 05:46:37PM +0300, Imre Deak wrote:
> Currently resuming on HSW from S3 pm_test/devices state leads to an
> unrecoverable GPU hang. Resetting the GPU during suspend fixes this. For
> a full S3 cycle this change only means the reset happens earlier (before
> reaching S3). For S4 the reset will happen now both during the freeze
> and quiesce phases, which is a benefit since it will guarantee that the
> GPU is idle before creating and loading the hibernation image.
> 
> Cc: Mika Kuoppala <mika.kuoppala at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Suggested-by: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Imre Deak <imre.deak at intel.com>

Makes sense, we should treat the transition to suspend just like unload.
We should do the symmetric reset on load/resume as well.

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre