https://bugs.freedesktop.org/show_bug.cgi?id=66963
--- Comment #23 from Alex Deucher agd5f@yahoo.com --- Created attachment 83246 --> https://bugs.freedesktop.org/attachment.cgi?id=83246&action=edit 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.