[Intel-gfx] [PATCH 3/3] drm/i915: peel dma-fence-chains wait fences

[Chris Wilson]

Quoting Lionel Landwerlin (2020-08-03 15:01:47)
> To allow faster engine to engine synchronization, peel the layer of
> dma-fence-chain to expose potential i915 fences so that the
> i915-request code can emit HW semaphore wait/signal operations in the
> ring which is faster than waking up the host to submit unblocked
> workloads after interrupt notification.
> 
> v2: Also deal with chains where the last node is not a dma-fence-chain

This is already done by i915_request_await_dma_fence.
-Chris