Unity makes usage of dual monitors impossible

[P. Czechowski]

I enlarge my Desktop by using a Samsung SyncMaster E1920 with my eeePC. (different pictures on each monitor) This works fine with the Gnome 2 shell. However, whenever I try to use the new Unity feature with dual monitors, both screens only show "scratches"/"pieces" of colour, and the system becomes totally unusable.

Description: Ubuntu 11.04
Release: 11.04

unity:
  Installiert: 3.8.12-0ubuntu1
  Kandidat: 3.8.12-0ubuntu1
  Versionstabelle:
 *** 3.8.12-0ubuntu1 0
        500 http://de.archive.ubuntu.com/ubuntu/ natty-updates/main i386 Packages
        100 /var/lib/dpkg/status
     3.8.10-0ubuntu2 0
        500 http://de.archive.ubuntu.com/ubuntu/ natty/main i386 Packages

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: xorg 1:7.6+4ubuntu3
ProcVersionSignature: Ubuntu 2.6.35-28.50-generic 2.6.35.11
Uname: Linux 2.6.35-28-generic i686
Architecture: i386
CompizPlugins: [core,bailer,detection,composite,opengl,decor,mousepoll,vpswitch,regex,animation,snap,expo,move,compiztoolbox,place,grid,imgpng,gnomecompat,wall,ezoom,workarounds,staticswitcher,resize,fade,unitymtgrabhandles,scale,session,unityshell]
CompositorRunning: None
DRM.card0.LVDS.1:
 status: connected
 enabled: enabled
 dpms: On
 modes: 1024x600
 edid-base64: AP///////wAiZOkDoAIAABETAQOAFg14CoA2ml5dkSggT1QAAAABAQEBAQEBAQEBAQEBAQEB7BMAzkBYJiBdIxUE3IEAAAAZAAAA/QA3QSIpBQAKICAgICAgAAAA/ABIU0QxMDBJRlcxCiAgAAAAEAAKICAgICAgICAgICAgAF4=
DRM.card0.VGA.1:
 status: connected
 enabled: enabled
 dpms: On
 modes: 1366x768 1024x768 1024x768 1024x768 832x624 800x600 800x600 800x600 800x600 640x480 640x480 640x480 640x480 720x400
 edid-base64: AP///////wBMLaMGODFCQyUUAQMOKRd4KrgRplVLmyUTUFS/7gABAQEBAQEBAQEBAQEBAQEBZiFWqlEAHjBGjzMAmuYQAAAeAAAA/QA4Sx49CQAKICAgICAgAAAA/ABTTUUxOTIwTgogICAgAAAA/wBIOUZaOTQ5ODUxCiAgAMk=
Date: Mon May 9 15:21:38 2011
DistUpgraded: Log time: 2011-05-02 19:32:53.597138
DistroCodename: natty
DistroVariant: ubuntu
GraphicsCard:
 Intel Corporation Mobile 945GME Express Integrated Graphics Controller [8086:27ae] (rev 03) (prog-if 00 [VGA controller])
   Subsystem: ASUSTeK Computer Inc. Device [1043:8340]
   Subsystem: ASUSTeK Computer Inc. Device [1043:8340]
InstallationMedia: Ubuntu-Netbook 10.10 "Maverick Meerkat" - Release i386 (20101007)
MachineType: ASUSTeK Computer INC. 1000HG
ProcEnviron:
 LANGUAGE=de_DE:en
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-2.6.35-28-generic root=UUID=a44c4272-3343-48e0-b130-0ef7b51b5e6a ro quiet splash vt.handoff=7
Renderer: Unknown
SourcePackage: xorg
Symptom: display
UpgradeStatus: Upgraded to natty on 2011-05-02 (6 days ago)
dmi.bios.date: 03/02/2009
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 0602
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: 1000HG
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: x.xx
dmi.chassis.asset.tag: 0x00000000
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTek Computer INC.
dmi.chassis.version: x.x
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr0602:bd03/02/2009:svnASUSTeKComputerINC.:pn1000HG:pvrx.x:rvnASUSTeKComputerINC.:rn1000HG:rvrx.xx:cvnASUSTekComputerINC.:ct10:cvrx.x:
dmi.product.name: 1000HG
dmi.product.version: x.x
dmi.sys.vendor: ASUSTeK Computer INC.
version.compiz: compiz 1:0.9.4+bzr20110415-0ubuntu2
version.libdrm2: libdrm2 2.4.23-1ubuntu6
version.libgl1-mesa-dri: libgl1-mesa-dri 7.10.2-0ubuntu2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.10.2-0ubuntu2
version.xserver-xorg: xserver-xorg 1:7.6+4ubuntu3
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.0-0ubuntu4
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.14.0-4ubuntu7.1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110107+b795ca6e-0ubuntu7

[astro (bernard-godard)]

same with Compaq Mini 110c 945GME graphics.
also the external monitor can be used alone but only up to 800x600: the screen is partially corrupted at higher resolutions. However it can be used in 1280x1024 on standard Gnome.

[astro (bernard-godard)]

Actually external monitor with Unity is also OK in 832x624 but not in 1024x768 and 1280x1024.
see xrandr information below:

Screen 0: minimum 320 x 200, current 832 x 624, maximum 4096 x 4096
LVDS1 connected (normal left inverted right x axis y axis)
   1024x600 60.0 +
   800x600 60.3 56.2
   640x480 59.9
VGA1 connected 832x624+0+0 (normal left inverted right x axis y axis) 338mm x 270mm
   1280x1024 60.0 + 75.0
   1024x768 75.1 70.1 60.0
   832x624 74.6*
   800x600 72.2 75.0 60.3 56.2
   640x480 72.8 75.0 66.7 60.0
   720x400 70.1

[astro (bernard-godard)]

UPDATE
external monitor display is not corrupted with KWin, XFCE and Gnome in 1024x768 and 1280x1024 but is corrupted in Unity. However, when using monitor in resolution 1024x768 and 1280x1024, playing videos in VLC, totem, xine, mplayer, mozilla-flash is extremely slow (below one frame per second). This might be related. It could be a regression in the Intel drivers since this was not a problem in ubuntu 10.04 and 10.10.

astro@lutetia:~$ glxinfo |grep -i rend
direct rendering: Yes
OpenGL renderer string: Mesa DRI Intel(R) 945GME GEM 20100330 DEVELOPMENT x86/MMX/SSE2
astro@lutetia:~$ xvinfo |grep maximum
    maximum XvImage size: 2048 x 2048
    maximum XvImage size: 2048 x 2048

[astro (bernard-godard)]

It seems to be fixed now.
I tried last week with same netbook and 2 different external monitors in 1280x1024 (taking care that total virtual screen is not larger than 2048x2048)
I haven't experienced this problem anymore.

[Sebastien Bacher (seb128)]

Could you try if that's still an issue in newer versions of Ubuntu?

[Tihomir Trifonov (ttrifonov)]

I'm not sure if this is the place to report this, but this bug seems relevant to the problem I'm experiencing.
Using raring beta, laptop thinkpad t400s with intel video and external monitor. Here are the steps to reproduce it:

1. I'm using the monitors in extended mode, no duplication.
2. I'm closing the lid of the laptop, thus the external becomes the main monitor.
3. Starting a video in full screen.
4. Opening the lid.

The video driver freezes, with "scratches" and random colors on screen, and keeps frozen even if I close again the lid, or disconnect the external monitor. No effect. The graphical env needs a restart to fix this. I definitely had no such problems with quantal.

Also, upon boot with dual monitor setup, after logging into the system, the screen stays shared between the two monitors(using half of each monitor) for a few seconds, and then gets ok on the both monitors. Not a critical issue, but this was introduced in raring. I haven't seen such issues in quantal too.