From: Chris Wilson Date: Wed, 7 Feb 2018 15:13:50 +0000 Subject: drm/i915: Mark the device as wedged from the beginning of set-wedged Git-commit: 0d73e7a095f768fad5a002bf6732c675e2aee44b Patch-mainline: v4.17-rc1 References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166 Reduce the window of opportunity for set-wedged being called concurrently with reset (after i915_reset() has performed the i915_gem_unset_wedged()) by moving the set_bit(I915_WEDGED) to before we complete the inflight requests. When i915_reset() is being blocked on a request, such completion may allow it to start and beginning resetting the GPU before i915_gem_set_wedged() has finished (and so before set-wedge will have marked the device as wedged). As such, i915_gem_init_hw() may see a wedged device even from inside i915_reset(). References: 36703e79a982 ("drm/i915: Break modeset deadlocks on reset") Signed-off-by: Chris Wilson Cc: Mika Kuoppala Cc: Joonas Lahtinen Cc: Tvrtko Ursulin Reviewed-by: Joonas Lahtinen Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20180207151350.20883-1-chris@chris-wilson.co.uk Acked-by: Petr Tesarik --- drivers/gpu/drm/i915/i915_gem.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -3213,6 +3213,9 @@ void i915_gem_set_wedged(struct drm_i915 intel_engine_dump(engine, &p, "%s\n", engine->name); } + set_bit(I915_WEDGED, &i915->gpu_error.flags); + smp_mb__after_atomic(); + /* * First, stop submission to hw, but do not yet complete requests by * rolling the global seqno forward (since this would complete requests @@ -3254,7 +3257,8 @@ void i915_gem_set_wedged(struct drm_i915 for_each_engine(engine, i915, id) { unsigned long flags; - /* Mark all pending requests as complete so that any concurrent + /* + * Mark all pending requests as complete so that any concurrent * (lockless) lookup doesn't try and wait upon the request as we * reset it. */ @@ -3266,7 +3270,6 @@ void i915_gem_set_wedged(struct drm_i915 i915_gem_reset_finish_engine(engine); } - set_bit(I915_WEDGED, &i915->gpu_error.flags); wake_up_all(&i915->gpu_error.reset_queue); }