Comment 16 for bug 285603

From dupe:

"Fglrx installer overwrites mesa and xserer files causing prombles with open source drivers even after removal. Solution would be install fglrx and open drivers to own subdirectories. Loading would either happen using symbolic links or /etc/ld.so.conf.d/ configuration. Also kernel modules should be blacklisted in /etc/modprobe.d/ when switching between drivers."