https://bugs.freedesktop.org/show_bug.cgi?id=49029
--- Comment #1 from Michel Dänzer michel@daenzer.net 2012-04-23 02:29:32 PDT ---
Apart from that it's working fine but the lack of power management reduce the run from a battery from 4h to 1h30.
I doubt it's all due to just that, but FWIW one thing you can try is radeon.dynclks=1 to enable clock gating.