https://bugzilla.kernel.org/show_bug.cgi?id=74551

--- Comment #9 from maxis11 ya.maxis11@yandex.ru --- (In reply to maxis11 from comment #8)

(In reply to Alex Deucher from comment #7)

...

Can you bisect?

All kernels 3.13.X ,3.14.X, 3.15-rc(1-8) are broken. 3.12 kernel started work from commit b2b8225e61d9176a5d08218842ce03c7be035176 (drm/radeon: 0x9649 is SUMO2 not SUMO)

3.12.7 - 3.12.20 working