I got XFree86 4.0.1 installed from the tar bins. With it is included a Matrox G400 driver (mga), a glx extension and a brand new OpenGL library.
Now the glx driver tells me that the extension 'GLX_SGI_video_sync' is supported. But there is no evidence of the SGI_video_sync extension functions as I understand them from the SGI man pages.
If I give a declaration of one of the SGI_video_sync functions it complains with undefined ref at link time.
Is this a dead end, the assumption being that the driver is lying?
Any other way you can think of to get vertical sync?
I think it's probably one of the *biggest* oversights in the GLX standard.