WARNING: at /build/buildd/linux-2.6.38/drivers/gpu/drm/radeon/radeon_fence.c:248 radeon_fence_wait+0x2ea/0x360 [radeon]()

When grabbing a pidgin window to move it my display turned from black to a frozen image of my desktop all the time. I had to restart the computer by pressing the power button on the laptop

ProblemType: KernelOops
DistroRelease: Ubuntu 11.04
Package: linux-image-2.6.38-8-generic-pae 2.6.38-8.41
Regression: Yes
Reproducible: Yes
ProcVersionSignature: Ubuntu 2.6.38-8.41-generic-pae 2.6.38.2
Uname: Linux 2.6.38-8-generic-pae i686
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
Annotation: Your system might become unstable now and might need to be restarted.
Architecture: i386
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: niclas 1334 F.... pulseaudio
CRDA: Error: [Errno 2] Datei oder Verzeichnis nicht gefunden
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf4500000 irq 48'
   Mixer name : 'Realtek ALC888'
   Components : 'HDA:10ec0888,10250205,00100202 HDA:11c11040,11c10001,00100200'
   Controls : 28
   Simple ctrls : 16
Card1.Amixer.info:
 Card hw:1 'HDMI'/'HDA ATI HDMI at 0xf4010000 irq 49'
   Mixer name : 'ATI R6xx HDMI'
   Components : 'HDA:1002aa01,00aa0100,00100100'
   Controls : 4
   Simple ctrls : 1
Card1.Amixer.values:
 Simple mixer control 'IEC958',0
   Capabilities: pswitch pswitch-joined penum
   Playback channels: Mono
   Mono: Playback [on]
Date: Wed Apr 6 20:42:07 2011
Failure: oops
HibernationDevice: RESUME=UUID=30b0fabb-fdbc-4212-ae7f-8acb0816f355
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Beta i386 (20110330)
MachineType: Acer Aspire 5738
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.38-8-generic-pae root=UUID=0bc05273-3ecd-4756-baee-baab64eb4e5c ro vga=792 quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-2.6.38-8-generic-pae N/A
 linux-backports-modules-2.6.38-8-generic-pae N/A
 linux-firmware 1.49
SourcePackage: linux
Title: WARNING: at /build/buildd/linux-2.6.38/drivers/gpu/drm/radeon/radeon_fence.c:248 radeon_fence_wait+0x2ea/0x360 [radeon]()
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/23/2009
dmi.bios.vendor: Phoenix Technologies LTD
dmi.bios.version: V1.21
dmi.board.name: JV50
dmi.board.vendor: Acer
dmi.board.version: Rev
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnPhoenixTechnologiesLTD:bvrV1.21:bd10/23/2009:svnAcer:pnAspire5738:pvr0100:rvnAcer:rnJV50:rvrRev:cvnAcer:ct10:cvrN/A:
dmi.product.name: Aspire 5738
dmi.product.version: 0100
dmi.sys.vendor: Acer