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); |
reqThe request to start some new work for
num_dwordsnumber of DWORDs that we plan to write to the ringbuffer.
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).