https://bugs.freedesktop.org/show_bug.cgi?id=73788
--- Comment #14 from Alex Deucher agd5f@yahoo.com --- (In reply to comment #12)
Alex it's here:
http://cgit.freedesktop.org/~agd5f/linux/commit/?h=drm-next-3.13- wip&id=4573388c92ee60b4ed72b8d95b73df861189988c
Does reverting that commit fix the problem?