https://bugs.freedesktop.org/show_bug.cgi?id=67994
--- Comment #18 from zimous zimous@matfyz.cz --- 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.