This is still an issue in Ubuntu 11.04 and 11.10beta2. Since I have uploaded fixes to the relevant compiz code recently, I have two suggestions that might fix this for compiz:
1. Switch GLX contexts at the right time. It seems like compiz is still in the context of screen 0 when it's doing the wait for sync on screen N>0. I got this idea from the official docs: http://www.opengl.org/registry/specs/SGI/video_sync.txt 2. Remove the old-fashioned Vsync waiting calls from compiz and use SGI_GLX_swap_control for everything: http://www.opengl.org/wiki/Swap_Interval http://www.opengl.org/registry/specs/SGI/swap_control.txt I have *partially* implemented #2 in compiz as part of the fix for bug 763005 already. However we won't be able to remove the Vsync waiting logic until/unless the compiz opengl plugin is changed to use glXSwapBuffers for every single frame. Presently compiz only calls glXSwapBuffers occasionally, so SGI_GLX_swap_control can't yet be used for all frames. -- You received this bug notification because you are a member of compiz packagers, which is subscribed to compiz in Ubuntu. https://bugs.launchpad.net/bugs/201342 Title: Tearing on secondary monitors even when "Sync To VBlank" is turned on. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/201342/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~compiz Post to : [email protected] Unsubscribe : https://launchpad.net/~compiz More help : https://help.launchpad.net/ListHelp

