tree e0693690f5c6633c7be9a967914e0d5dd83fe743
parent a4f968d8e50cb7810e08ebb9bf4c8f2b769fdac7
author Egbert Eich <eich@suse.de> 1350128174 +0000
committer Dave Airlie <airlied@redhat.com> 1353391669 +1000

DRM/KMS: Add Bail-Out Conditions for Loop.

When trying to obtain an accurate timestamp for the last vsync interrupt
in vblank_disable_and_save() we loop until the vsync counter after reading
the time stamp is identical to the one before.
In the case where no hardware timestamp can be obtained there is probably
no point in trying to make sure we remain within the same vsync during
the time we obtain the counter.
Furthermore we should make sure there's an 'emergency exit' so that we
don't end up in an endless loop when the driver get_vblank_timestamp()
function doesn't manage to return within the same vsync.
This may happen when this function prints out debugging information over
a slow (ie serial) line.

Signed-off-by: Egbert Eich <eich@suse.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>