[Intel-gfx] [PATCH 3/6] drm/i915/gt: Allow failed resets without assertion

[Andi Shyti]

Hi Chris,

On Mon, Jan 04, 2021 at 11:51:42AM +0000, Chris Wilson wrote:
> If the engine reset fails, we will attempt to resume with the current
> inflight submissions. When that happens, we cannot assert that the
> engine reset cleared the pending submission, so do not.
> 
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2878
> Fixes: 16f2941ad307 ("drm/i915/gt: Replace direct submit with direct call to tasklet")
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/gt/intel_engine_types.h  |  2 +
>  .../drm/i915/gt/intel_execlists_submission.c  |  6 +-
>  drivers/gpu/drm/i915/gt/intel_reset.c         |  3 +
>  drivers/gpu/drm/i915/gt/selftest_execlists.c  | 75 +++++++++++++++++++
>  4 files changed, 85 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> index c28f4e190fe6..430066e5884c 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
> @@ -561,6 +561,8 @@ struct intel_engine_cs {
>  		unsigned long stop_timeout_ms;
>  		unsigned long timeslice_duration_ms;
>  	} props, defaults;
> +
> +	I915_SELFTEST_DECLARE(struct fault_attr reset_timeout);
>  };
>  
>  static inline bool
> diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> index 2afbc0a4ca03..f02e3ae10d28 100644
> --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
> @@ -3047,9 +3047,13 @@ static void execlists_reset_finish(struct intel_engine_cs *engine)
>  	 * After a GPU reset, we may have requests to replay. Do so now while
>  	 * we still have the forcewake to be sure that the GPU is not allowed
>  	 * to sleep before we restart and reload a context.
> +	 *
> +	 * If the GPU reset fails, the engine may still be alive with requests
> +	 * inflight. We expect those to complete, or for the device to be
> +	 * reset as the next level of recovery, and as a final resort we
> +	 * will declare the device wedged.
>  	 */
>  	GEM_BUG_ON(!reset_in_progress(execlists));
> -	GEM_BUG_ON(engine->execlists.pending[0]);

I would have split this in two patches, but it looks good anyway.

Reviewed-by: Andi Shyti <andi.shyti at intel.com>

Thanks,
Andi