On Dec 23, 2011, at 3:39 PM, ext Holger Hans Peter Freyther wrote: >> >> It is a known issue that sometimes graphics drivers don't have vsync enabled >> by default. In this case, it will render as fast as possible, usually giving >> 1000s of FPS and 100% CPU usage. On my machine (ubuntu 10.04 with nvida >> drivers), I was able to fix this by toggling 'sync to vblank' in the nvidia- >> settings applications. > > Can this be detected somehow? I think I ended up in this issue as on one > suspend/resume cycle the GPU hang and the X11/intel driver disabled > acceleration. > I don't ask for a workaround like limiting the FPS but just to detect an > unrealistic/broken driver behavior. I am looking at this from two point of > views: Users and Qt Integrators. In both cases it would be nice to detect such > a problem in one way or another.
The easiest place to detect this would be to add some logic to qquickwindowmanager.cpp where the animations are advanced. If the delta between when that code runs is less than 16 ms for more than a few frames in a row, then it would imply a non-blocking driver and we could issue a warning. How does that sound? cheers, Gunnar _______________________________________________ Development mailing list [email protected] http://lists.qt-project.org/mailman/listinfo/development
