Hello, On Fri, Jul 08, 2016 at 02:52:30PM +0900, Michel Dänzer wrote: > On 07.07.2016 16:43, Christian König wrote: > >>> Also, what kind of delays matter here? Is it millisec range or micro? > >> It can be the latter in theory, but normally rather the former. > > > > Well to be precise with a typical 1920x1080@60 resolution you have about > > 2.16ms time under ideal conditions for the flip. > > > > So using the high priority queue still sounds like a good idea to me. > > How did you arrive at 2.16ms? > > Userspace can call the ioctl up to one full refresh cycle ahead of time, > which is ~16ms at 60 Hz. On the other hand userspace can also call the > ioctl arbitrarily close to the vertical blank period, in which case even > a delay of just 1ms (or even significantly less) may cause the flip to > be delayed by one refresh cycle. If there's too long a delay, the outcome is missing the refresh cycle, right? Hmmm... yeah, WQ_HIGHPRI probably is the right answer here. Bhaktipriya, can you please update the patch to use a dedicated workqueue with WQ_HIGHPRI? Thanks. -- tejun _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
