When a flip (or unflip) is pending and a flip request comes in, leave
it queued until the pending flip completes and then execute it.
This fixes a bug where an application submitting back-to-back
present_pixmap requests for sequential frames would alternate between
flipping and copying as the pending flip would cause the new
present_pixmap request to not use a flip.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Frank Binns <frank.binns@imgtec.com>