> for A/V-sync I'm measuring the frame rate of current screen with > two WaitForSync() calls. for VIA unichrome I get some strange result: > A/V sync seems to be OK (no frames dropped) when time is set hardcoded. > Without that I'll get: > > [dfb] Display frame time is 99949 microseconds > [dfb] Display frame time is 99950 microseconds
OK, I think I know what's happening there. Which framebuffer driver are you using? The 'patcher2k' version of viafb (and possibly other versions too) has a bug in it. The vblank interrupt is enabled and a handler installed but the interrupt then gets disabled again when the video mode is set up. Thus the driver gets no interrupts at all. The 0.1 second interval you are seeing is the wait timeout that's there to prevent a complete hang in the event that the interrupt never arrives. If you look at one of the earlier unichrome threads, you'll find a patch for that version of viafb that I posted. It should fix this problem (as well as providing improved tv-out capability and the option of frame syncs). If you only want to fix this bug, you should be able to find the appropriate part of the patch to apply but if not, get back to me and I'll post further details. Regards, Mark _______________________________________________ directfb-users mailing list [email protected] http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-users
