i915_request_await_dma_fence
err = i915_request_await_dma_fence(eb->request, fence);
err = i915_request_await_dma_fence(eb.request, in_fence);
ret = i915_request_await_dma_fence(to, excl);
ret = i915_request_await_dma_fence(to, shared[i]);
int i915_request_await_dma_fence(struct i915_request *rq,