https://bugs.freedesktop.org/show_bug.cgi?id=69775
--- Comment #4 from Alex Deucher agd5f@yahoo.com --- (In reply to comment #3)
Retested with
Kernel 3.13-rc1 + drm-radeon-fix-typo-in-fetching-mpll-params.patch
That patch only affects SI and CI parts so something else must have fixed it.