i have big Xinerama problems.
i am running pretty standard Red Hat 8 with two video cards (a GeForce3 and a TNT2 M64), and two monitors.
under 31 series drivers Xinerama worked fine, i upgraded to 4191 from tar files over the existing setup. same XF86Config.
now some apps cause the system to hang - seems to happen when one app has several windows open, and one window crosses the boundary between monitors.
i was able to provoke the crash by running mozilla full screen on monitor 1, starting a download (which opened a download dialog on monitor 2), then dragging the download dialog across to monitor 1. after first redraw of dialog edge on monitor1, system freezes.
starting gnome-terminal seems to provoke the crash regardless of geometry settings.
RedHat 8.0 (no kernel upgrade)
AGP card = Geforce3 (ASUSv8200 deluxe)
PCI card = TNT2 M64
CPU Athlon 1700+
VIA K7T266 Pro2 mobo