Comment 25 for bug 586243

Same symptoms here as in bug description.

$ lspci -d 1002: -vvvmmk
Slot: 01:00.0
Class: VGA compatible controller
Vendor: ATI Technologies Inc
Device: NI Caicos [AMD RADEON HD 6450]
Rev: ff
ProgIf: ff
Driver: radeon
Module: radeon

Slot: 01:00.1
Class: Audio device
Vendor: ATI Technologies Inc
Device: NI Caicos HDMI Audio [AMD RADEON HD 6450]
Rev: ff
ProgIf: ff
Driver: HDA Intel

$ uname -a
Linux rlibby 3.0.0-15-generic #26-Ubuntu SMP Fri Jan 20 17:23:00 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 11.10
Release: 11.10
Codename: oneiric
$ dpkg -s xserver-xorg | grep Version
Version: 1:7.6+7ubuntu7.1
$ dpkg -s xserver-xorg-video-radeon | grep Version
Version: 1:6.14.99~git20110811.g93fc084-0ubuntu1