On Mon, Feb 18, 2013 at 01:57:51PM +0200, ville.syrjala at linux.intel.com wrote: > From: Ville Syrj?l? <ville.syrjala at linux.intel.com> > > If the interrupt handler were to process a previous vblank interrupt and > the following flip pending interrupt at the same time, the page flip > would be complete too soon. > > To eliminate this race check the live pending flip status from the ISR > register before finishing the page flip. Ok, that makes a lot of sense. /* We detect FlipDone by looking for the change in PendingFlip from '1' * to '0' on the following vblank, i.e. IIR has the Pendingflip * asserted following the MI_DISPLAY_FLIP, but ISR is deasserted, hence * the flip is completed (no longer pending). Since this doesn't raise an * interrupt per-se, we watch for the change at vblank. */ > Signed-off-by: Ville Syrj?l? <ville.syrjala at linux.intel.com> Reviewed-by: Chris Wilson <chris at chris-wils Time to give it a quick test and make sure it doesn't break a ton of assumptions... :) -Chris -- Chris Wilson, Intel Open Source Technology Centre
