Comment # 14 on bug 76286 from OmegaPhil+FreeDesktop.BugTracker@gmail.com

I noticed v3.13.7-1 has come to Debian testing today with the following in the
changelog:

   - drm/radeon: fix runpm disabling on non-PX harder
      (may fix #741619, #742507)

I can confirm it doesnt help when I get rid of 'radeon.dpm=0' on boot.