unity garbled screen when external monitor attached

[Rory Timar]

Binary package hint: compiz

While running the default unity desktop with the latest updated 11.04, an attempt to attach an external monitor to this laptop garbles both displays. Sometimes, moving the mouse over on open window will reveal its contents. Also, compiz hogs close to 100% cpu. This problem exists in ubuntu with unity, and ubuntu classic, but not in ubuntu classic without effects.

Some hopefully relavant information:
compiz version: 1:0.9.4+bzr20110415-0ubuntu2

the line "intel(0): Failed to set tiling on frontbuffer" in /var/log/Xorg.0.log

glxinfo -l | grep GL_MAX_TEXTURE_SIZE:
GL_MAX_TEXTURE_SIZE = 2048

messages from compiz after killing and relaunching it in a terminal:
GLRenderbuffer::GLRenderbuffer() ERROR: size too big width=2704height=1050 <- this message occured while loading
compiz (opengl) - Info: Couldn't bind redirected window 0x1200024 to texture <- this message occurs constantly

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: compiz 1:0.9.4+bzr20110415-0ubuntu2
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-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
DRM.card0.LVDS.1:
 status: connected
 enabled: enabled
 dpms: On
 modes: 1366x768
 edid-base64: AP///////wBMo1IwAAAAAAATAQOAGxB4CjUlk1ZVjikdUFQAAAABAQEBAQEBAQEBAQEBAQEBqxtWgFAAFjAwICUAAJAQAAAZAAAADwAAAAAAAAAAAB60AnQAAAAA/gBTQU1TVU5HCiAgICAgAAAA/gAxMTZBVDAxLVAwMQogAA==
DRM.card0.VGA.1:
 status: connected
 enabled: enabled
 dpms: On
 modes: 1680x1050 1280x1024 1280x1024 1440x900 1280x960 1280x800 1152x864 1024x768 1024x768 1024x768 832x624 800x600 800x600 800x600 800x600 640x480 640x480 640x480 640x480 720x400
 edid-base64: AP///////wAEaaoic2YCABEUAQNoLx54KscgpFVJmScTUFS/7wBxT4FAgYCVALMAgQABAQEBCDmQMGIaJ0AYsDZA2SgRAAAcAAAA/wBBNExNVEYxNTcyOTkKAAAA/QA3Sx5VEAAKICAgICAgAAAA/ABBU1VTIFZXMjI0CiAgAOA=
Date: Thu Jun 2 12:13:54 2011
DistUpgraded: Fresh install
DistroCodename: natty
DistroVariant: ubuntu
GraphicsCard:
 Intel Corporation N10 Family Integrated Graphics Controller [8086:a011] (prog-if 00 [VGA controller])
   Subsystem: Intel Corporation Device [8086:a001]
   Subsystem: Intel Corporation Device [8086:a001]
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
InstallationMedia_: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
MachineType: Zareason Corporation PT20
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_US:en
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-8-generic root=UUID=e7612404-b80b-499e-98fb-eb8f3082877a ro quiet splash vt.handoff=7
ProcVersionSignature_: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Renderer: Unknown
SourcePackage: compiz
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/10/2010
dmi.bios.vendor: Phoenix Technologies LTD
dmi.bios.version: PT20_B1.1.216_E1.1.351_P0
dmi.board.asset.tag: Not Applicable
dmi.board.name: PT20
dmi.board.vendor: Zareason Corporation
dmi.board.version: MP
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 1
dmi.chassis.vendor: Zareason Corporation
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnPhoenixTechnologiesLTD:bvrPT20_B1.1.216_E1.1.351_P0:bd03/10/2010:svnZareasonCorporation:pnPT20:pvrMP:rvnZareasonCorporation:rnPT20:rvrMP:cvnZareasonCorporation:ct1:cvrN/A:
dmi.product.name: PT20
dmi.product.version: MP
dmi.sys.vendor: Zareason Corporation
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