[Intel-gfx] [PATCH 3/5] drm/i915/execlists: Process interrupted context on reset

[Tvrtko Ursulin]

On 16/07/2019 13:49, Chris Wilson wrote:
> By stopping the rings, we may trigger an arbitration point resulting in
> a premature context-switch (i.e. a completion event before the request
> is actually complete). This clears the active context before the reset,
> but we must remember to rewind the incomplete context for replay upon
> resume.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>   drivers/gpu/drm/i915/gt/intel_lrc.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
> index 9b87a2fc186c..7570a9256001 100644
> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
> @@ -1419,7 +1419,8 @@ static void process_csb(struct intel_engine_cs *engine)
>   			 * coherent (visible from the CPU) before the
>   			 * user interrupt and CSB is processed.
>   			 */
> -			GEM_BUG_ON(!i915_request_completed(*execlists->active));
> +			GEM_BUG_ON(!i915_request_completed(*execlists->active) &&
> +				   !reset_in_progress(execlists));
>   			execlists_schedule_out(*execlists->active++);
>   
>   			GEM_BUG_ON(execlists->active - execlists->inflight >
> @@ -2254,7 +2255,7 @@ static void __execlists_reset(struct intel_engine_cs *engine, bool stalled)
>   	 */
>   	rq = execlists_active(execlists);
>   	if (!rq)
> -		return;
> +		goto unwind;
>   
>   	ce = rq->hw_context;
>   	GEM_BUG_ON(i915_active_is_idle(&ce->active));
> @@ -2331,6 +2332,7 @@ static void __execlists_reset(struct intel_engine_cs *engine, bool stalled)
>   	intel_ring_update_space(ce->ring);
>   	__execlists_update_reg_state(ce, engine);
>   
> +unwind:
>   	/* Push back any incomplete requests for replay after the reset. */
>   	__unwind_incomplete_requests(engine);
>   }
> 

Sounds plausible.

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Shouldn't there be a Fixes: tag to go with it?

Regards,

Tvrtko