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[Bug 212587] Re: Vsync setting has no effect


Alright, so there are actually a couple issues here. Let me see if I can
clear them all up.

1) nVidia's OpenGL Sync to VBlank option only affects glXSwapBuffers but
we don't use it. In order to use this option we would have to do a full
screen redraw every frame and while AaronP might think this isn't a
problem we don't all have nVidia graphics cards. Even if we did use this
option it would only help compiz and not any videos or OpenGL
applications compiz is managing. There is currently no way to ensure
such things are flicker free when using any compositor as you don't want
to sync to vblank but to the compositor's redraw rate. As you cannot get
this information from the compositor there is no way to even try to do
this. See http://dri.freedesktop.org/wiki/CompositeSwap for all the gory

That pretty much wraps it all up, actually. Just a couple more little

2) The compiz way of doing sync to vblank doesn't guarantee vsync if
your computer is under heavy load. There is no way to fix this with what
we have available right now. It also "fights" with the nvidia-settings
sync to vblank option.

3) We don't enable sync to vblank in compiz by default because in the
past it caused suspend/resume issues with nvidia cards and right now it
causes intel users to get about 0.5 frames per second. Even if we did
enable it by default it wouldn't help with the issues most of you seem
to be having.

Vsync setting has no effect
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