Change of screen resolution results in grafik disruption

[Jens Herrmann]

I use a Thinkpad R500 (2731-A11) with an external screen attached to the docking station. In about 1 out of 5 cases I get graphic disruption on the internal screen when I change the screen resolution (using arandr) for the external screen to the native resolution 1920x1200. It looks like this: https://www.youtube.com/watch?v=JwPGBCJqqvE&feature=youtu.be
Note that the external screen is not affected by this. Sometimes this also occurs when I boot the system just before the graphical login manager should appear.
I also noticed that it is possible to regain the internal screen with "echo mid | sudo tee /sys/class/drm/card0/device/power_profile" from the terminal. While the screen is visible now this results in a ghost image and I have to reboot to fix this.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: xserver-xorg-video-radeon 1:7.3.0-1ubuntu3.1
ProcVersionSignature: Ubuntu 3.13.0-24.47-generic 3.13.9
Uname: Linux 3.13.0-24-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.4
Architecture: amd64
CurrentDesktop: XFCE
Date: Sun Sep 21 08:03:35 2014
EcryptfsInUse: Yes
InstallationDate: Installed on 2013-11-26 (298 days ago)
InstallationMedia: Xubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016)
SourcePackage: xserver-xorg-video-ati
UpgradeStatus: Upgraded to trusty on 2014-04-22 (151 days ago)

[Jens Herrmann (bugs-u)]

I forgot, which log files do you need?

[penalvch (penalvch)]

Jens Herrmann, thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command, as it will automatically gather debugging information, in a terminal:
apport-collect -p xorg 1372031

Please ensure you have the package xdiagnose installed, and that you click the Yes button for attaching additional debugging information.

[Launchpad Janitor (janitor)]

[Expired for xorg (Ubuntu) because there has been no activity for 60 days.]