>
> It simply works without any trick. It also works with stock kernel 3.13. Are
> you sure that you have the same ATI card?
>
No, I have Radeon R7 260X, so it uses RadeonSI mesa driver. But I did some
research and it appears Radeon DPM is now turned on by default (on latest
kernel 3.15) and people complain abount non-working /proc variables everywhere.
So sadly, currently there's no clue for me.