https://bugs.freedesktop.org/show_bug.cgi?id=79223
--- Comment #10 from Pierre Ossman pierre-bugzilla@ossman.eu --- Ok, some kind of progress. The call that is causing the delay now is glUseProgram(0);. It grows gradually from no latency up to 17 ms (i.e. one frame @ 60 Hz). Then it goes back down again and the cycle repeats.
Ideas?