[PATCH 1/3] drm/scheduler: fix a corner case in dependency optimization

[Christian König]

Am 25.05.2018 um 06:45 schrieb Nayan Deshmukh:
> When checking for a dependency fence for belonging to the same entity
> compare it with scheduled as well finished fence. Earlier we were only
> comparing it with the scheduled fence.
>
> Signed-off-by: Nayan Deshmukh <nayan26deshmukh at gmail.com>

Reviewed and pushed this patch into our internal repository.

Now going to take a look at the rest,
Christian.

> ---
>   drivers/gpu/drm/scheduler/gpu_scheduler.c | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/scheduler/gpu_scheduler.c b/drivers/gpu/drm/scheduler/gpu_scheduler.c
> index df1578d6f42e..44d480768dfe 100644
> --- a/drivers/gpu/drm/scheduler/gpu_scheduler.c
> +++ b/drivers/gpu/drm/scheduler/gpu_scheduler.c
> @@ -349,8 +349,13 @@ static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity)
>   	struct dma_fence * fence = entity->dependency;
>   	struct drm_sched_fence *s_fence;
>   
> -	if (fence->context == entity->fence_context) {
> -		/* We can ignore fences from ourself */
> +	if (fence->context == entity->fence_context ||
> +            fence->context == entity->fence_context + 1) {
> +                /*
> +                 * Fence is a scheduled/finished fence from a job
> +                 * which belongs to the same entity, we can ignore
> +                 * fences from ourself
> +                 */
>   		dma_fence_put(entity->dependency);
>   		return false;
>   	}