Public bug reported: >> What's the problem?
When opening Unity's Dash in Ubuntu 16.04 (either by clicking on the uppermost icon of the launcher called “Search” or by a keyboard shortcut “Super + Tab”), the display of a connected external monitor (3440x1440, 21:9) turns completely black if, and only if there is another window (e.g. with Firefox, gedit, Nautilus) beneath the just opening dash. The monitor also goes into stand-by. When closing the Dash (e.g. by pressing the Esc key – while the display is black) the monitor will display the desktop again. The black screen bug also appears when activating Unity's “spreading all windows” function by clicking on such launcher icons which has more than one instance of an application opened (e.g. two terminals are opened) and if there remain other windows beneath (e.g. gedit window). This problem does not occur with Ubuntu <= 15.10 ! ------------------------------------------------- >> How to reproduce the bug? Use a Lenovo Thinkpad T450s with a ThinkPad Pro Dock. Leave the laptop lid closed and connect an external monitor (e.g. a Dell U3415W) via DisplayPort 1.2; use monitors native resolution which is 3440x1440 with 60 Hz. Start Ubuntu 16.04 (either from a LiveUSB/LiveCD stick or from a partition where Ubuntu is installed incl. all updates). Open one or more windows, e.g. with Firefox, gedit, Nautilus, and place them in the upper left corner of the display where the Dash usually appears when opening it. Then open the Dash (with mouse click or shortcut). BANG -> the whole screen turns black. Press Esc to close the Dash and colours come back. The bug also happens when using dual monitoring. In this case only the display with 3440x1440 turns black when opening the Dash. This bug doesn't appear when only using the notebooks build in display. Again: This problem does not occur with Ubuntu <= 15.10 ! ------------------------------------------------- >> What work arounds did I figure out? 1) Pressing Esc key will close the Dash, which brings back the picture. But with this work around the Dash is still useless of course. 2) Minimize all windows (e.g. by pressing the launcher's icon “Show Desktop”). Then the Dash appears and the display doesn't turn black – because there are no windows underneath the Dash. Of course this could be a temporary workaround, but in the long run it would be very annoying to have minimized all windows before using the Dash. 3) When changing the monitors resolution to 2560x1080 the bug will not appear. This could be only a temporary workaround, because I'm not using a large-scale monitor to have a ancient resolution. 4) Using a complete different desktop than Unity, e.g. Cinnamon or Gnome, which is a pity, because I get used to Unity. Once again: - This problem (black screen) does not occur with Ubuntu <= 15.10 ! - The bug is not caused due to my personal configurations of Ubuntu, because the bug occurs with a Ubuntu 16.04 LiveUSB as well as with a installed Ubuntu incl. all updates. - The bug seems not to appear with resolutions smaller than 3440x1440 (but I haven't tested where exactly the limits lie). ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: unity 7.4.0+16.04.20160906-0ubuntu1 ProcVersionSignature: Ubuntu 4.4.0-64.85-generic 4.4.44 Uname: Linux 4.4.0-64-generic x86_64 .tmp.unity_support_test.0: ApportVersion: 2.20.1-0ubuntu2.5 Architecture: amd64 BootLog: 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: Fri Feb 24 08:48:19 2017 DistUpgraded: Fresh install DistroCodename: xenial DistroVariant: ubuntu GraphicsCard: Intel Corporation Broadwell-U Integrated Graphics [8086:1616] (rev 09) (prog-if 00 [VGA controller]) Subsystem: Lenovo Broadwell-U Integrated Graphics [17aa:5036] InstallationDate: Installed on 2016-09-23 (153 days ago) InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1) MachineType: LENOVO 20BX0011GE ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-64-generic.efi.signed root=UUID=e515c051-7a9a-44d4-bb0e-a63486526c63 ro noprompt quiet splash vt.handoff=7 SourcePackage: unity UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 05/21/2015 dmi.bios.vendor: LENOVO dmi.bios.version: JBET49WW (1.14 ) dmi.board.asset.tag: Not Available dmi.board.name: 20BX0011GE dmi.board.vendor: LENOVO dmi.board.version: SDK0E50510 WIN dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: None dmi.modalias: dmi:bvnLENOVO:bvrJBET49WW(1.14):bd05/21/2015:svnLENOVO:pn20BX0011GE:pvrThinkPadT450s:rvnLENOVO:rn20BX0011GE:rvrSDK0E50510WIN:cvnLENOVO:ct10:cvrNone: dmi.product.name: 20BX0011GE dmi.product.version: ThinkPad T450s dmi.sys.vendor: LENOVO upstart.unity7.log: WARN 2017-02-24 08:46:04 unity.iconloader IconLoader.cpp:756 Unable to load icon file:/// at size -1x22: Can't open directory ATTENTION: default value of option force_s3tc_enable overridden by environment. WARN 2017-02-24 08:48:01 unity.iconloader IconLoader.cpp:264 Unable to load icon qmlscene at size 64 version.compiz: compiz 1:0.9.12.2+16.04.20160823-0ubuntu1 version.ia32-libs: ia32-libs N/A version.libdrm2: libdrm2 2.4.70-1~ubuntu16.04.1 version.libgl1-mesa-dri: libgl1-mesa-dri 12.0.6-0ubuntu0.16.04.1 version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A version.libgl1-mesa-glx: libgl1-mesa-glx 12.0.6-0ubuntu0.16.04.1 version.xserver-xorg-core: xserver-xorg-core 2:1.18.4-0ubuntu0.2 version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2 version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.0-1 version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20160325-1ubuntu1.2 version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-1build2 xserver.bootTime: Fri Feb 24 08:44:08 2017 xserver.configfile: default xserver.errors: xserver.logfile: /var/log/Xorg.0.log xserver.outputs: product id 4925 vendor AUO xserver.version: 2:1.18.4-0ubuntu0.2 ** Affects: unity (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug compiz-0.9 ubuntu xenial -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1667593 Title: Display Turns Black When Unity's Dash is opened (16.04 LTS) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/unity/+bug/1667593/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs