https://bugs.freedesktop.org/show_bug.cgi?id=41248

--- Comment #2 from Leann Ogasawara leann.ogasawara@canonical.com 2011-09-29 09:49:40 PDT --- Just adding relevant information here. Gustav has tested and confirmed that reverting the following two patches resolves the issue:

commit d5811e8731213f80c80d89e980505052f16aca1c Author: Alex Deucher alexander.deucher@amd.com Date: Sat Aug 13 13:36:13 2011 -0400

drm/radeon/kms: don't try to be smart in the hpd handler

commit 73104b5cfe3067d68f2c2de3f3d4d4964c55873e Author: Alex Deucher alexander.deucher@amd.com Date: Tue Aug 9 17:09:06 2011 +0000

drm/radeon/kms: don't enable connectors that are off in the hotplug handler

Gustav has also tested and confirmed the issue remains in the latest v3.1-rc8 upstream kernel.