Comment # 24 on bug 82201 from Christian König

(In reply to comment #23)
> (In reply to comment #22)
> > do you have radeon.dpm=0 in smoe /etc/modprobe.d or somewhere like that file?
> 
> No:
> # grep -nHr radeon.dpm /etc/*
> /etc/default/grub:9:GRUB_CMDLINE_LINUX_DEFAULT="quiet radeon.dpm=1"

What's the result of "cat /sys/module/radeon/parameters/dpm" when you don't
specify the "radeon.dpm=1" on the kernel commandline?