Connecting external monitor causes primary display to garble

[Jeff Lane ]

I believe this is not specific to the Latitude 2120. Running Oneiric Alpha 3 and when I plug a monitor in to the external VGA port, the display becomes garbled. Using the UI at this point is impossible. Also, the secondary display only shows the bar at the top and a black screen, no background is presented.

The only remedy is to remove the external monitor, at which point, Unity resets itself and becomes usable again.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: unity 4.6.0-0ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-8.10-generic 3.0.1
Uname: Linux 3.0.0-8-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: compiz
Date: Tue Aug 9 13:20:30 2011
DistUpgraded: Fresh install
DistroCodename: oneiric
DistroVariant: ubuntu
GraphicsCard:
 Intel Corporation N10 Family Integrated Graphics Controller [8086:a011] (rev 02) (prog-if 00 [VGA controller])
   Subsystem: Dell Device [1028:04a5]
   Subsystem: Dell Device [1028:04a5]
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Alpha i386 (20110803.1)
LightdmGreeterLog:

MachineType: Dell Inc. Latitude 2120
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.0.0-8-generic root=UUID=08fbc92a-95f3-46a5-b5ea-ea48d3df5663 ro quiet splash initcall_debug vt.handoff=7
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/06/2010
dmi.bios.vendor: Dell Inc.
dmi.bios.version: W06
dmi.board.name: DOE3C2
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrW06:bd10/06/2010:svnDellInc.:pnLatitude2120:pvr:rvnDellInc.:rnDOE3C2:rvr:cvnDellInc.:ct8:cvr:
dmi.product.name: Latitude 2120
dmi.sys.vendor: Dell Inc.
version.compiz: compiz 1:0.9.5.0-0ubuntu2
version.libdrm2: libdrm2 2.4.26-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 7.11-0ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.11-0ubuntu1
version.xserver-xorg: xserver-xorg 1:7.6+7ubuntu6
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.6.0-1ubuntu13
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.2-1ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.15.0-3ubuntu2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110411+8378443-1

[Omer Akram (om26er)]

Reproduced quite the same issue yesterday with my netbook which have the same intel GPU. compiz was using 100% cpu

[Jeff Lane  (bladernr)]

For the record, I've now seen this on two systems using Intel N10 GPUs and one system with an ATI GPU... so it's not limited to just one chip or driver.

[Omer Akram (om26er)]

This bug I believe is the same as bug 769650 which says its the hardware limitation as the issue does not happen if the monitors are set in 'One above the other' or 'mirror displays' is ticked. Ubuntu could do things gracefully. bug 555641 is also on a similar issue.