https://bugs.freedesktop.org/show_bug.cgi?id=66963
--- Comment #167 from Nicola nicolamori@aol.com --- (In reply to comment #166)
(In reply to comment #165)
radeon.audio=0 radeon.aspm=0 radeon.dpm=1
It didn't work with my Mobility HD3470. Two hangs out 5 reboots.
I forgot to mention that I'm using kernel 3.12.6 (with ck patches). Maybe is kernel 3.13 that does the magic together with the kernel command line options?