Eh, now I realized that this bug is also about DPM.  In my case "radeon.dpm=0"
does not help.  Sorry for that, I should have filed a new bug.

Also, after more testing it seems that 4.1.0-rc-2 + drm-fixes behaves more like
4.0.2 + patch.  It depends, sometimes Ctrl+F1 / restart X / clean poweroff is
possible, sometimes not.