On 02.04.2015 20:34, Chris Wilson wrote: > On vblank instant-off systems, we can get into a situation where the cost > of enabling and disabling the vblank IRQ around a drmWaitVblank query > dominates. However, we know that if the user wants the current vblank > counter, they are also very likely to immediately queue a vblank wait > and so we can keep the interrupt around and only turn it off if we have > no further vblank requests in the interrupt interval. > > After vblank event delivery there is a shadow of one vblank where the > interrupt is kept alive for the user to query and queue another vblank > event. Similarly, if the user is using blocking drmWaitVblanks, the > interrupt will be disabled on the IRQ following the wait completion. > However, if the user is simply querying the current vblank counter and > timestamp, the interrupt will be disabled after every IRQ and the user > will enabled it again on the first query following the IRQ. As I mentioned before, it might not be too hard to make querying the current counter work without enabling the interrupt. But this looks like a step in the right direction. Acked-by: Michel Dänzer <michel.daenzer@xxxxxxx> -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
