[Intel-gfx] [PATCH 01/28] drm/i915: Adjust the sentinel assert to match implementation

[Tvrtko Ursulin]

On 07/06/2020 23:20, Chris Wilson wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> Sentinels are supposed to be last reqeusts in the elsp queue, not the
> only one, so adjust the assert accordingly.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>   drivers/gpu/drm/i915/gt/intel_lrc.c | 14 +++-----------
>   1 file changed, 3 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
> index d55a5e0466e5..db8a170b0e5c 100644
> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
> @@ -1635,9 +1635,9 @@ assert_pending_valid(const struct intel_engine_execlists *execlists,
>   		ccid = ce->lrc.ccid;
>   
>   		/*
> -		 * Sentinels are supposed to be lonely so they flush the
> -		 * current exection off the HW. Check that they are the
> -		 * only request in the pending submission.
> +		 * Sentinels are supposed to be the last request so they flush
> +		 * the current exection off the HW. Check that they are the only
> +		 * request in the pending submission.
>   		 */
>   		if (sentinel) {
>   			GEM_TRACE_ERR("%s: context:%llx after sentinel in pending[%zd]\n",
> @@ -1646,15 +1646,7 @@ assert_pending_valid(const struct intel_engine_execlists *execlists,
>   				      port - execlists->pending);
>   			return false;
>   		}
> -
>   		sentinel = i915_request_has_sentinel(rq);

FWIW I was changing it to "sentinel |= ..." so it keeps working if we 
decide to use more than 2 elsp ports on Icelake one day.

Regards,

Tvrtko

> -		if (sentinel && port != execlists->pending) {
> -			GEM_TRACE_ERR("%s: sentinel context:%llx not in prime position[%zd]\n",
> -				      engine->name,
> -				      ce->timeline->fence_context,
> -				      port - execlists->pending);
> -			return false;
> -		}
>   
>   		/* Hold tightly onto the lock to prevent concurrent retires! */
>   		if (!spin_trylock_irqsave(&rq->lock, flags))
>