Comment # 9 on bug 1189174 from Fabian Vogt

Some more input from upstream:

> Video game based render loop is unsuitable for kwin and other wayland compositors that try to maintain the balance between the responsiveness (latency) and the smoothness. kwin needs reasonable presentation timestamps to function as expected. If the pageflip callback is called immediately, it's fine, but kwin needs the timestamp to have a reasonable value (slightly in the future) in that case.

> Does the drm driver even report any timestamp at all? If it were to report zero, we could maybe handle this in a not completely broken way, but if it reports a valid timestamp, it has to roughly match the mode we set the CRTC to.