Comment 2 for bug 776978

Same problem on a DELL E4200.
I was also unable to switch on an external display of 1920x1200 (and switch off laptop screeen). I finally succeed in removing monitors.xml in .config, and restart xorg. I suspect the bug is more related to compiz than xorg.
(I've also try to add an output of correct resolution in the general setting of compiz, tab display settings, ... not sure whether this has changed something)

PCI (sysfs)
  *-display:0
       description: VGA compatible controller
       product: Mobile 4 Series Chipset Integrated Graphics Controller
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 07
       width: 64 bits
       clock: 33MHz
       capabilities: msi pm vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:45 memory:f6c00000-f6ffffff memory:e0000000-efffffff ioport:ef98(size=8)
  *-display:1 UNCLAIMED
       description: Display controller
       product: Mobile 4 Series Chipset Integrated Graphics Controller
       vendor: Intel Corporation
       physical id: 2.1
       bus info: pci@0000:00:02.1
       version: 07
       width: 64 bits
       clock: 33MHz
       capabilities: pm bus_master cap_list
       configuration: latency=0
       resources: memory:f6b00000-f6bfffff
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=11.04
DISTRIB_CODENAME=natty
DISTRIB_DESCRIPTION="Ubuntu 11.04"