Screen garbled after changing display settings

[Furkan]

On my dual-monitor setup, changing the display settings to turn off the secondary display results in the main display becoming entirely garbled and unusable. Waiting for the 20 seconds to elapse causes the configuration to revert to the previous configuration, but then both screens are garbled and unusable until I switch to a virtual terminal and run "sudo service lightdm restart".

The effect can be observed in the following video: https://www.dropbox.com/s/49cx1qm67tzjojy/VID_20150405_165947.mp4?dl=0

I am using a Radeon R7 260X, with the open-source radeonsi driver.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: xorg 1:7.7+7ubuntu4
ProcVersionSignature: Ubuntu 3.19.0-12.12-generic 3.19.3
Uname: Linux 3.19.0-12-generic x86_64
.tmp.unity.support.test.0:

ApportVersion: 2.17-0ubuntu1
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Sun Apr 5 17:01:37 2015
DistUpgraded: 2015-03-27 18:17:09,531 DEBUG enabling apt cron job
DistroCodename: vivid
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, including running git bisection searches
GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] Bonaire XTX [Radeon R7 260X] [1002:6658] (prog-if 00 [VGA controller])
   Subsystem: VISIONTEK Device [1545:7260]
InstallationDate: Installed on 2014-06-06 (302 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
MachineType: Gigabyte Technology Co., Ltd. GA-970A-D3
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.19.0-12-generic root=UUID=d254b01f-2bf2-4b57-acdc-c796786f4c4c ro
SourcePackage: xorg
Symptom: display
UpgradeStatus: Upgraded to vivid on 2015-03-27 (8 days ago)
dmi.bios.date: 12/16/2013
dmi.bios.vendor: Award Software International, Inc.
dmi.bios.version: F13b
dmi.board.name: GA-970A-D3
dmi.board.vendor: Gigabyte Technology Co., Ltd.
dmi.board.version: x.x
dmi.chassis.type: 3
dmi.chassis.vendor: Gigabyte Technology Co., Ltd.
dmi.modalias: dmi:bvnAwardSoftwareInternational,Inc.:bvrF13b:bd12/16/2013:svnGigabyteTechnologyCo.,Ltd.:pnGA-970A-D3:pvr:rvnGigabyteTechnologyCo.,Ltd.:rnGA-970A-D3:rvrx.x:cvnGigabyteTechnologyCo.,Ltd.:ct3:cvr:
dmi.product.name: GA-970A-D3
dmi.sys.vendor: Gigabyte Technology Co., Ltd.
version.compiz: compiz 1:0.9.12.1+15.04.20150330-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.59-0ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 10.5.2-0ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 10.5.2-0ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.17.1-0ubuntu3
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.9.0-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.5.0-1ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917-1~exp1ubuntu2build1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.11-1ubuntu2build1
xserver.bootTime: Sun Apr 5 17:00:57 2015
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.17.1-0ubuntu3
xserver.video_driver: radeon

[Furkan (falaca)]

I booted up into the latest Kubuntu 15.04 daily build, and while the corruption still occurs when changing display settings, unlike Unity it seems to recover afterwards (the background gets messed up as you can see from the video, but at least the desktop remains usable): https://www.dropbox.com/s/cganqpegygseo6r/VID_20150408_182602.mp4?dl=0

[Furkan (falaca)]

I upgraded a bunch of packages today (did a dist-upgrade, which brought in updated libdrm* packages and a bunch of other stuff, and I also installed the 3.19.0-13 kernel from the testing PPA) and this is now resolved. I have no idea which update fixed it, but at least it's gone (hopefully for good)!

[Furkan (falaca)]

Oops... Never mind. Changing my monitor's position works fine, but changing the resolution results in a black screen. So the behaviour seems to have changed slightly, but the issue still exists.

[Christopher M. Penalver (penalvch)]

Furkan, thank you for reporting this and helping make Ubuntu better. To if this is already resolved in Ubuntu, could you please test http://cdimage.ubuntu.com/daily-live/current/ and advise to the results?

[Furkan (falaca)]

Christopher, I'm running Wily beta right now, and the issue is resolved.

[Christopher M. Penalver (penalvch)]

Furkan, this bug report is being closed due to your last comment https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/1440606/comments/6 regarding this being fixed with an update. For future reference you can manage the status of your own bugs by clicking on the current status in the yellow line and then choosing a new status in the revealed drop down box. You can learn more about bug statuses at https://wiki.ubuntu.com/Bugs/Status. Thank you again for taking the time to report this bug and helping to make Ubuntu better. Please submit any future bugs you may find.