intel_logical_ring_begin — prepare the logical ringbuffer to accept some commands
int intel_logical_ring_begin ( | struct drm_i915_gem_request * req, |
int num_dwords) ; |
The ringbuffer might not be ready to accept the commands right away (maybe it needs to be wrapped, or wait a bit for the tail to be updated). This function takes care of that and also preallocates a request (every workload submission is still mediated through requests, same as it did with legacy ringbuffer submission).