Very similar to http://bugs.freedesktop.org/show_bug.cgi?id=2166 The difference is that I get nplanes = 24 as I'm running at 24 bit depth. quake4 and doom3 no longer work - they fail with GLX: cannot find visual errors. Strangely, ET and AA play just fine. Using ati-drivers-8.22 and 8.23 on amd64. Reverting to xorg-server-1.0.1-r4 fixes, quake4 and doom3 work again.
This could be a problem with the ATI drivers.
If this isn't fixed with xorg-server-1.0.2-r3, please reopen.
Works now, thanks :)