Originally Posted by d_u_s_t
"update each area of my screen separately"? can you give more details about that and your hw setup? sounds like it might be another problem
Sorry, I should have clarified that post a little better.
I have not used the patch that was posted in this thread. Though it sounds very promising, I am using a binary distribution and really don't want to manage a custom build of xorg. Instead, I just hacked my xorg.conf a bit to force the nVidia driver to report fake Xinerama info.
What I expect from fake Xinerama is that Gnome will understand the boundaries of my physical monitors. Gnome should maximize windows to a single monitor or snap to the monitor edges as I move windows. And, my hack did that.
But one side effect was that 3-d rendering (Mesa?) appeared to treat the 3 monitors as 3 separate rendering devices. When GL screen savers would kick on, I could see each physical monitor fade to black separately instead of synchronously. It has been a few months since I tried this, but I believe that the GL lattice screen saver would function across all 3 monitors as one large structure, though the animation seemed slow and it looked as if the image for each monitor was being rendered separately. Whereas, without my Xinerama hack, the rendering is quite smooth and the monitors appear to be a single display.
As I proofread this post, it still seems confusing. But, I can't think of a better way to describe this phenomenon.