Gnome desktop freeze / hangup after calling xrandr

Binary package hint: gdm

My report is somehow related to Bug #617421 however, effect more critical and including data loss.

From time to time it happens that the screen shortly flickers and a second monitor gets detected (by mistake).

It happens even without touching mouse or keyboard - this time I was taking notes on paper.

The screen/monitor that gets detected can be TV1 when I am working on my laptop only or LVDS1 when I am in docking station with external monitor attached and laptop lid closed (LVDS1 is the laptop-builtin-monitor/screen).

When I then call xrandr for example using:
xrandr --output HDMI1 --mode 1680x1050 --rate 60 --primary --output LVDS1 --off --output TV1 --off --output VGA1 --off --output HDMI2 --off --output DP1 --off --output DP1 --off --output DP2 --off --output DP3 --off

(in this case to switch to the external monitor only), the Gnome desktop completely freezes / locks up. Switching to a text console with CTRL+ALT+F1 for example, does not work either. Mouse pointer does not move - nothing. I have to switch off the laptop and restart.

Unfortunately this is not reproducable - it does not occur always. Often the xrandr call is successful without freezing everything.

The only thing I can tell so far is that I am pretty sure, that always, when it happens the VirtualBox is started with at least one virtual machine being up (with a Windows guest). I also tried disabling all acceleration features within VirtualBox (2D and 3D), remote display disabled - and I gave 63 MB of video memory which should be enough. Monitor count is set to 1.

Contents of compreg.dat is:
[HEADER]
Version,0,5

[COMPONENTS]
rel:VBoxSVCM.so,1286550763000
rel:VBoxC.so,1286550763000
rel:VBoxXPCOMIPCC.so,1238375354000,VBoxXPCOM.so libpthread.so libdl.so

[CLASSIDS]
{d9e56bf8-e32e-4b6d-87f1-06d73b0ce7ca},,,,rel:VBoxXPCOMIPCC.so
{1403adf4-94d1-4c67-a8ae-d9f86972d378},,,,rel:VBoxXPCOMIPCC.so
{9f12676a-5168-4a08-beb8-edf8a593a1ca},,,,rel:VBoxXPCOMIPCC.so
{b1a7a4f2-47b9-4a1e-82b2-07ccd5323c3f},,,,rel:VBoxSVCM.so
{3c02f46d-c9d2-4f11-a384-53f0cf917214},,,,rel:VBoxC.so
{49ee8561-5563-4715-b18c-a4b1a490dafe},,,,rel:VBoxC.so
{63a5d9dc-4828-425a-bd50-bd10a4b26f2c},@mozilla.org/ipc/dconnect-service;1,,ipcDConnectService,rel:VBoxXPCOMIPCC.so

[CONTRACTIDS]
@virtualbox.org/Session;1,{3c02f46d-c9d2-4f11-a384-53f0cf917214}
@mozilla.org/ipc/lock-service;1,{d9e56bf8-e32e-4b6d-87f1-06d73b0ce7ca}
@mozilla.org/ipc/service;1,{9f12676a-5168-4a08-beb8-edf8a593a1ca}
@virtualbox.org/CallbackWrapper;1,{49ee8561-5563-4715-b18c-a4b1a490dafe}
@virtualbox.org/VirtualBox;1,{b1a7a4f2-47b9-4a1e-82b2-07ccd5323c3f}
@mozilla.org/ipc/dconnect-service;1,{63a5d9dc-4828-425a-bd50-bd10a4b26f2c}
@mozilla.org/ipc/transaction-service;1,{1403adf4-94d1-4c67-a8ae-d9f86972d378}

[CATEGORIES]
xpcom-startup,ipcDConnectService,@mozilla.org/ipc/dconnect-service;1

Attached VirtualBox.xml - for the case it helps

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: gdm 2.30.2.is.2.30.0-0ubuntu4
ProcVersionSignature: Ubuntu 2.6.32-25.45-generic 2.6.32.21+drm33.7
Uname: Linux 2.6.32-25-generic i686
Architecture: i386
Date: Tue Nov 2 10:00:52 2010
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
ProcEnviron:
 LC_TIME=en_DK.utf8
 LANGUAGE=en
 LANG=en_US.utf8
 SHELL=/bin/bash
SourcePackage: gdm