[Intel-gfx] [PATCH 3/7] drm/i915: Signal fence completion from i915_request_wait

[Tvrtko Ursulin]

On 19/06/2019 12:23, Chris Wilson wrote:
> With the upcoming change to automanaged i915_active, the intent is that
> whenever we wait on the set of active fences, they are signaled and
> collected.  The requirement is that all successful returns from
> i915_request_wait() signal the fence, so fixup the one remaining path
> where we may return before the interrupt has been run.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_request.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
> index 0c2b53b8a3d1..8d59c35bd22f 100644
> --- a/drivers/gpu/drm/i915/i915_request.c
> +++ b/drivers/gpu/drm/i915/i915_request.c
> @@ -1451,8 +1451,10 @@ long i915_request_wait(struct i915_request *rq,
>   	for (;;) {
>   		set_current_state(state);
>   
> -		if (i915_request_completed(rq))
> +		if (i915_request_completed(rq)) {
> +			dma_fence_signal(&rq->fence);
>   			break;
> +		}
>   
>   		if (signal_pending_state(state, current)) {
>   			timeout = -ERESTARTSYS;
> 

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

Patch is fine, but I have to say commit message scares me a bit. Where 
are we adding such subtle fragility that wait has to exit with fence 
signaled? Is it just some specific i915_request_wait call site or all of 
them?

Regards,

Tvrtko