Screen contents "flickering" after screen turned back on

[Nicolai Hähnle]

The following happened after the screen turned itself off (based on the configured delay) and then on again due to keyboard/mouse activity: The image on the screen rapidly switched back and forth between two slightly different images. By moving the mouse around (causing UI elements to react), more and more regions became "stable" again, until the whole image on the screen was stable in the end.

Unfortunately, the behaviour is non-deterministic: I cannot reproduce it reliably.

In any case, the behaviour is consistent with Unity doing some optimizations based on information about the page flipping behaviour of the framebuffer as obtained by GLX_EXT_buffer_age. It's possible that restoring from the turned off screen is not implemented correctly. A similar bug seems to have been fixed recently in KWin, see the discussion at the end of https://bugs.freedesktop.org/show_bug.cgi?id=97119 (which includes a video).

This is with a single 1920x1080 screen, on an AMD Polaris10, with oibaf PPA (i.e. open-source) drivers.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: unity 7.4.0+16.04.20160801.2-0ubuntu1
Uname: Linux 4.7.0amd-staging-4.7 x86_64
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.1
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: Tue Sep 6 13:05:31 2016
DistUpgraded: 2016-04-27 22:48:29,120 ERROR got error from PostInstallScript ./xorg_fix_proprietary.py (g-exec-error-quark: Failed to execute child process "./xorg_fix_proprietary.py" (No such file or directory) (8))
DistroCodename: xenial
DistroVariant: ubuntu
GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] Device [1002:67df] (rev c4) (prog-if 00 [VGA controller])
   Subsystem: Advanced Micro Devices, Inc. [AMD/ATI] Device [1002:0b31]
InstallationDate: Installed on 2015-11-27 (283 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
MachineType: To be filled by O.E.M. To be filled by O.E.M.
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.7.0amd-staging-4.7 root=/dev/mapper/ubuntu--vg-root ro quiet splash vt.handoff=7
SourcePackage: unity
UpgradeStatus: Upgraded to xenial on 2016-04-28 (131 days ago)
dmi.bios.date: 03/24/2015
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 2601
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: M5A97 LE R2.0
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev 1.xx
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr2601:bd03/24/2015:svnTobefilledbyO.E.M.:pnTobefilledbyO.E.M.:pvrTobefilledbyO.E.M.:rvnASUSTeKCOMPUTERINC.:rnM5A97LER2.0:rvrRev1.xx:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.name: To be filled by O.E.M.
dmi.product.version: To be filled by O.E.M.
dmi.sys.vendor: To be filled by O.E.M.
version.compiz: compiz 1:0.9.12.2+16.04.20160801.3-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.70+git1608300630.3106a3~gd~x
version.libgl1-mesa-dri: libgl1-mesa-dri 12.1~git1609010730.e3db41~gd~x
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 12.1~git1609010730.e3db41~gd~x
version.xserver-xorg-core: xserver-xorg-core 2:1.18.3-1ubuntu2.3
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.99+git1608290731.a92c27~gd~x
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git1608291931.74e4c1~gd~x
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12+git1607191931.6473b6~gd~x
xserver.bootTime: Tue Sep 6 07:35:03 2016
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.18.3-1ubuntu2.3
xserver.video_driver: amdgpu

[Drew Freiberger (afreiberger)]

I am also seeing this on yakkety with three displays. As I move the mouse, the background flickers on two or three of the monitors. tends toward the lower-right than the upper left. A right-click on the desktop (bringing up the desktop sub-menu) clears the error immediately for me until the sleep-wake cycle happens again. This does not happen when I only use my internal laptop screen.