Unity or X hangs when trying to change xrandr properties

[Dan Smith]

Binary package hint: unity

Attaching additional 1600x1200 monitor to VGA port on the laptop. Go into the monitor tool and disable the laptop display, enable the VGA port at 1600x1200@60Hz. Hit apply, get a blank screen (this exact configuration used to work on 10.10). Wait for the timeout or hit escape and get another blank screen but with a mouse cursor that moves. Nothing else ever shows up. Reboot or restart GDM is the only way out. Running the following at a terminal inside of X works fine:

xrandr --output VGA1 --auto
xrandr --output LVDS1 --off

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: unity 3.8.10-0ubuntu2
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic x86_64
Architecture: amd64
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.DP.1:
 status: disconnected
 enabled: disabled
 dpms: Off
 modes:
 edid-base64:
DRM.card0.HDMI.A.1:
 status: disconnected
 enabled: disabled
 dpms: Off
 modes:
 edid-base64:
DRM.card0.LVDS.1:
 status: connected
 enabled: enabled
 dpms: Off
 modes: 1280x800 1280x800
 edid-base64: AP///////wAwrhFAAAAAAAATAQOAGhB46lzVk1xejiccUFQAAAABAQEBAQEBAQEBAQEBAQEB7hoAgFAgEDAQMBMABaMQAAAZ0BcAxlAgGTAwIDYABaMQAAAZAAAADwCBCjyBCjIWCQBMo0FUAAAA/gBMVE4xMjFBVDA3TDAyADg=
DRM.card0.VGA.1:
 status: connected
 enabled: enabled
 dpms: On
 modes: 1600x1200 1280x1024 1280x1024 1152x864 1024x768 1024x768 800x600 800x600 640x480 640x480 720x400
 edid-base64: AP///////wAQrCCgTDA5MgcRAQMOKR947u6Ro1RMmSYPUFSlSwCBgKlAcU8BAQEBAQEBAQEBSD9AMGKwMkBAwBMAbxMRAAAeAAAA/wBDOTUzNjcyRjI5MEwKAAAA/ABERUxMIDIwMDdGUAogAAAA/QA4TB5TEQAKICAgICAgAGg=
Date: Fri Apr 22 11:15:58 2011
DistUpgraded: Fresh install
DistroCodename: natty
DistroVariant: ubuntu
GraphicsCard:
 Intel Corporation Core Processor Integrated Graphics Controller [8086:0046] (rev 02) (prog-if 00 [VGA controller])
   Subsystem: Lenovo Device [17aa:215a]
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Beta amd64 (20110413)
InstallationMedia_: Ubuntu 11.04 "Natty Narwhal" - Beta amd64 (20110413)
InstallationMedia__: Ubuntu 11.04 "Natty Narwhal" - Beta amd64 (20110413)
MachineType: LENOVO 362613U
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/zsh
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-8-generic root=UUID=060c7c97-7a38-4ec4-b372-d5ddc8a4cad5 ro quiet splash vt.handoff=7
ProcVersionSignature_: Ubuntu 2.6.38-8.42-generic 2.6.38.2
ProcVersionSignature__: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Renderer: Unknown
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/15/2010
dmi.bios.vendor: LENOVO
dmi.bios.version: 6QET53WW (1.23 )
dmi.board.name: 362613U
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr6QET53WW(1.23):bd09/15/2010:svnLENOVO:pn362613U:pvrThinkPadX201:rvnLENOVO:rn362613U:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 362613U
dmi.product.version: ThinkPad X201
dmi.sys.vendor: LENOVO
version.compiz: compiz 1:0.9.4+bzr20110415-0ubuntu2
version.ia32-libs: ia32-libs 20090808ubuntu12
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
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110107+b795ca6e-0ubuntu7