https://bugs.freedesktop.org/show_bug.cgi?id=77394
--- Comment #13 from nine@detonation.org --- After two months with a stable system using fglrx, I gave radeon a try again. I can still easily reproduce the GPU lockups using kernel 3.16.0-rc2-5.g19015a0-desktop and radeon_ucode fetched today. dmesg output changed a litte. Maybe this helps?