tree 831529a147ec7cd85ae080e415a84b351af574fe
parent 1741dd4aa7552055659bf74ab829a21579407f10
author Chris Wilson <chris@chris-wilson.co.uk> 1280931493 +0100
committer Eric Anholt <eric@anholt.net> 1281378271 -0700

drm/i915: Move ringbuffer accounting to begin/advance.

As we check that the ringbuffer will not wrap upon emission, we do not
need to check that incrementing the tail wrapped every time. However, we
do upon advancing just in case the tail is now pointing at the very end
of the ring.

Likewise we can account for the space used during emission in begin()
and avoid decrementing it for every emit.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Eric Anholt <eric@anholt.net>