Ubuntu locks up on continuous screen brightness change

[Umang Varma]

I have been able to reproduce this bug three out of three times in the last ten minutes. Using the function keys that change the laptop screen brightness (basically F4 and F5 without the 'Fn' key), to continuously change the brightness (i.e. holding the keys down continuously), I am able to lock the computer up COMPLETELY. By completely, I mean that the computer responds to no input (Ctrl+Alt+F1 doesn't nothing, mouse doesn't move) and is frozen (e.g music playing on Spotify gets stuck and plays continuous noise).

I can also reproduce this by closing all unessential applications indicators also. (It takes a few more seconds of trying if the indicators are closed).

I don't know any means to ssh into my own machine, so I cannot give you the dmesg log.

Ubuntu 12.04
Dell N5010 laptop
unity 5.12-0ubuntu1.1
compiz 1:0.9.7.8-0ubuntu1

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: unity 5.12-0ubuntu1.1
ProcVersionSignature: Ubuntu 3.2.0-25.40-generic-pae 3.2.18
Uname: Linux 3.2.0-25-generic-pae i686
NonfreeKernelModules: wl
.tmp.unity.support.test.0:

ApportVersion: 2.0.1-0ubuntu8
Architecture: i386
CompizPlugins: [core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,unitymtgrabhandles,workarounds,scale,expo,ezoom,unityshell]
CompositorRunning: compiz
Date: Tue Jun 19 21:28:36 2012
DistUpgraded: Fresh install
DistroCodename: precise
DistroVariant: ubuntu
DkmsStatus:
 bcmwl, 5.100.82.38+bdcom, 3.2.0-24-generic-pae, i686: installed
 bcmwl, 5.100.82.38+bdcom, 3.2.0-25-generic-pae, i686: installed
GraphicsCard:
 Intel Corporation Core Processor Integrated Graphics Controller [8086:0046] (rev 18) (prog-if 00 [VGA controller])
   Subsystem: Dell Device [1028:0447]
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release i386 (20120423)
Lsusb:
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
 Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
 Bus 001 Device 003: ID 0c45:641d Microdia 1.3 MPixel Integrated Webcam
MachineType: Dell Inc. Inspiron N5010
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-25-generic-pae root=UUID=6b3b0b1b-f942-4d29-bb66-96318091a70e ro quiet splash vt.handoff=7
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/26/2010
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A07
dmi.board.name: 0WXY9J
dmi.board.vendor: Dell Inc.
dmi.board.version: A07
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: A07
dmi.modalias: dmi:bvnDellInc.:bvrA07:bd07/26/2010:svnDellInc.:pnInspironN5010:pvrA07:rvnDellInc.:rn0WXY9J:rvrA07:cvnDellInc.:ct8:cvrA07:
dmi.product.name: Inspiron N5010
dmi.product.version: A07
dmi.sys.vendor: Dell Inc.
version.compiz: compiz 1:0.9.7.8-0ubuntu1
version.libdrm2: libdrm2 2.4.32-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 8.0.2-0ubuntu3.1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 8.0.2-0ubuntu3.1
version.xserver-xorg-core: xserver-xorg-core 2:1.11.4-0ubuntu10.2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.0-0ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.99~git20111219.aacbd629-0ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.17.0-1ubuntu4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20111201+b5534a1-1build2

[Umang Varma (umang)]

I just tried changing the screen brightness through the "Brightness and Lock" application and Ubuntu locked up again.

[Umang Varma (umang)]

On second thought, I think this is xorg related.

I'm using xorg version 1:7.6+12ubuntu1