[Intel-gfx] [PATCH 2/2] drm/i915: Dump the engine state before declaring wedged from wait_for_engines()

[Chris Wilson]

Quoting Joonas Lahtinen (2017-12-12 13:40:25)
> On Mon, 2017-12-11 at 19:41 +0000, Chris Wilson wrote:
> > If wait_for_engines() fails and we resort to declaring the HW wedged,
> > dump the engine state for debugging.
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> > Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> 
> Reviewed-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>

Ta for the review. I've worked through to the immediate cause of the
problem, so if you would like to review

drm/i915: Don't check #active_requests from i915_gem_wait_for_idle()
drm/i915: Mark up potential allocation paths within i915_sw_fence as might_sleep
drm/i915: Allow fence allocations to fail
drm/i915: Ratelimit request allocation under oom

and

igt/gem_shrink: Exercise allocations in the middle of execbuf under oom-pressure

next, that would be grand. A fine piece of cheese, Gromit.

I'm still puzzling how such a simple piece of code managed to get into
so much trouble in the first place. I suppose it was able to fill 3
rings with a few 10k requests each, which is definitely more than enough
to run into oom on that machine. Ok, not such a mystery after all.
-Chris