On Tue, Nov 04, 2014 at 12:04:03PM +0100, Daniel Vetter wrote: > On Tue, Oct 28, 2014 at 03:10:14PM +0200, Ander Conselvan de Oliveira wrote: > > @@ -9400,7 +9419,7 @@ static int intel_queue_mmio_flip(struct drm_device *dev, > > struct intel_crtc *intel_crtc = to_intel_crtc(crtc); > > int ret; > > > > - if (WARN_ON(intel_crtc->mmio_flip.seqno)) > > + if (WARN_ON(intel_crtc->mmio_flip.status != INTEL_MMIO_FLIP_IDLE)) > > return -EBUSY; > > Ok I've merged the patch, but I think this check is wrong. do_mmio_flip > only sets this to idle _after_ the hw register writing is done. Which > means the flip could complete and userspace could receive the event all > before we set status to IDLE. Which means you can WARN and return -EBUSY > here when the flip definitely completed. > > So either clear IDLE at the head of do_mmio_flip before doing anything, or > drop this state again. After all the previous seqno check only looked for > waiting or not. tbh I'm not even sure whether this buys us anything at all > - we already check that the flip completed, which should ensure ordering. > I think we could just rip out mmio_flip.status completely. > > Can you pls do a fixup patch? A better strategy would be to use the generic seqno mechanism for the flip from a worker which then wouldn't need this extra vblank state machinery on top of the vblank evade... -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
