Comment 13 for bug 546578

Forwarding this bug from Ubuntu reporter Guillaume Giroux:
http://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/546578

[Problem]
Screen goes black after switching from primary to secondary user and back several times. Occurs regardless of whether KMS or compiz are enabled or disabled.

[Original Description]
Up-to-date Lucid with radeon driver. After switching user a few times (usually between 3 and 5 times), the screen goes black with only the mouse cursor visible after entering the user's password. VTs are also completely black. Restarting gdm fixes the issue, and nothing odd appears in XOrg.0.log when the black screen occurs.

- It also happens with KMS disabled.
- It also happens with compiz disabled for all users.

Another user adds that they see the same issue on an Xpress 200m, and finds the black screen always happens on the return to the primary user, never in the primary->secondary user case.

Architecture: i386
Date: Wed Mar 24 21:43:21 2010
DistroRelease: Ubuntu 10.04
DkmsStatus: Error: [Errno 2] No such file or directory
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release i386 (20091028.5)
Lsusb:
 Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: Hewlett-Packard HP dx5150 MT(PV753AA)
Package: xorg 1:7.5+3ubuntu1
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-17-generic root=UUID=2f620498-4095-49f2-8ea6-7355f3d696ec ro
ProcEnviron:
 LANG=en_US.utf8
 ProcVersionSignature: Ubuntu 2.6.32-17.26-generic 2.6.32.10+drm33.1
SourcePackage: xorg
Uname: Linux 2.6.32-17-generic i686
dmi.bios.date: 03/08/2007
dmi.bios.vendor: Phoenix Technologies, LTD
dmi.bios.version: 1.19
dmi.board.name: 09AC
dmi.board.vendor: MSI
dmi.chassis.type: 3
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnPhoenixTechnologies,LTD:bvr1.19:bd03/08/2007:svnHewlett-Packard:pnHPdx5150MT(PV753AA):pvr:rvnMSI:rn09AC:rvr:cvnHewlett-Packard:ct3:cvr:
dmi.product.name: HP dx5150 MT(PV753AA)
dmi.sys.vendor: Hewlett-Packard
system:
  codename: lucid
 architecture: i686
 kernel: 2.6.32-17-generic