drm: add some comments to drm_wait_vblank and drm_queue_vblank_event
authorIlija Hadzic <ihadzic@research.bell-labs.com>
Mon, 31 Oct 2011 17:11:57 +0000 (13:11 -0400)
committerDave Airlie <airlied@redhat.com>
Fri, 11 Nov 2011 11:16:30 +0000 (11:16 +0000)
commita6778e9e7fb57603f15344ceb30098a3f6b7caf4
tree1422443322e6bd119edab9db60dc6ae2e3d3b29f
parentbfba16582600ab2c75dc39250a2b8f3b2a42da11
drm: add some comments to drm_wait_vblank and drm_queue_vblank_event

during the review of the fix for locks problems in drm_wait_vblank,
a couple of false concerns were raised about how the drm_vblank_get
and drm_vblank_put are used in this function; it turned out that the
code is correct and that it cannot be simplified

add a few comments to explain non-obvious flows in the code,
to prevent "false alarms" in the future

v2: incorporate comments received from Daniel Vetter

Signed-off-by: Ilija Hadzic <ihadzic@research.bell-labs.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
drivers/gpu/drm/drm_irq.c