Comment 87 for bug 838577

I had some success with 11.12 as well. I can't declare full victory because I am having trouble using dual monitors with it--seeing some problems with Gnome Shell that I am not seeing under unity such as flickering and freezing (sometimes only on the external monitor). But in general, I can use Gnome Shell with this version. I downloaded the driver directly from AMD at http://support.amd.com/us/gpudownload/linux/Pages/radeon_linux.aspx.

I followed these instructions, which were somewhat simpler than others I have seen (though it doesn't do all of the uninstalling that some of the other instruction sets I have seen do), to install it: http://mygeekopinions.blogspot.com/2011/06/how-to-install-atiamd-catalyst-linux.html

Obviously I substituted the current filenames for the older ones in the instructions. But install and reboot and I was able to see Gnome Shell with perfect clarity, not with garbled menus and crazy stripes, etc.