https://bugs.freedesktop.org/show_bug.cgi?id=66963
--- Comment #165 from Kajzer kap3tan@gmail.com --- Hello, I had problems with just radeon.dpm=1 , as soon as I hit enter screen would go black and monitor would blink like there was no connection, it was either that or it would just reboot. Anyway, after adding this line : radeon.audio=0 radeon.aspm=0 radeon.dpm=1 everything works GREAT ! Several reboots (to be sure) and it worked every time. Played few games on Steam, watched couple of videos and everything works fine without any issues.
some info : sensors : radeon-pci-0400 Adapter: PCI adapter temp1: +49.0°C (crit = +120.0°C, hyst = +90.0°C)
/sys/kernel/debug/dri/64/radeon_pm_info: uvd vclk: 0 dclk: 0 power level 0 sclk: 11000 mclk: 80000 vddc: 900
using this kernel : 3.13.0-rc3-7.gfbe0eb5-desktop
video card is : Radeon HD 3650
Don't know what else I can say about it, if you need more info I will be more that happy to help :)