Comment # 23 on bug 66963 from Alex Deucher

Created attachment 83246 [details] [review]
hacks to test

That attached patch disables some options in the dpm driver.  See if it helps
at all.  Make sure you are using a kernel that contains the fixes mentioned in
comment 9 or my drm-fixes-3.11 branch.

If the patch doesn't work as is, try changing the:
#if 1
in the patch to:
#if 0
and see if that helps.

Please attach your dmesg output with the patch applied.