Comment 8 for bug 404428

There is no regression, r600_dri.so was never provided in any version of mesa in ubuntu ever. You have always been using swrast if you use the free drivers for 3D operations. Composite and 3D are not exactly the same thing, xrender based compositing via metacity or kwin or xcompmgr will work fine with r600 using -ati or -radeonhd (the latter requires forcing DRI in your xorg.conf) but compiz only provides GL compositing so it uses software rendering and will always be slow in that situation. The bug reporter posted glxgears performance numbers saying it was low, and glxgears is a 3D application. DRI will work for 2D acceleration, but AIGLX for hardware accelerated GL compositing will not work. I marked it invalid because this is a "will not fix" bug in karmic, there is no r600_dri.so outside of mesa 7.6 and it requires a very specific libdrm and only works on 2.6.28 kernels right now (not to mention it is about as buggy as it can get). They are looking to integrate the kernel specific things in 2.6.32, but unfortunately karmic will ship with 2.6.31. deadspider187, if you have low performance in 2D then you should file a seperate bug report regarding that because it is a different issue entirely.

The propriatary drivers do work fine with xserver 1.6, you want to install them through the package manager via the fglrx-installer package and not straight from ATI though. Unfortunately fglrx is not working at the moment on the 2.6.31 kernels in karmic, so you will have to go back to 2.6.30-10.12 if you want to use it until it is updated.