Comment 0 for bug 980058

WHAT HAPPENED INSTEAD:
======================
Since upgrading from Ubuntu 11.10 to 12.04, while booting, Plymouth is displayed fine, there are no problems there. The problem occurs when Plymouth finishes and Lightdm should start. 9 times out of 10, Lightdm starts fine and everything works OK.

However, occasionally instead of Lightdm starting, the screen shows a white box in the centre of the screen, surrounded by black bands.

moving the mouse leaves vertical artefacts on the screen, which makes me think that X/Lightdm hasn't froze, but I see no HDD activity when I enter my password and press enter (Maybe Lightdm crashes, leaving X (and mouse input) working fine?).

Switching to any TTY clears the screen, however the only thing visible is a blinking vertical band (which moves along as I type my user-name and password to try to log in through a TTY)

From here I run:
  sudo shutdown -h now
and enter my password again.

The computer then restarts and is back to normal.

The next time this happens I will try running:
  sudo pkill x
To see if that can cause X to restart and show normally.

I will attach a photo I took, and some mockups of the behavior in the TTY terminal.

WHAT I EXPECTED TO HAPPEN:
=========================
I expected the computer to show Lightdm and allow me to log in normally and use my computer
(which it does do, nearly most of the time)

lsb_release -rd
===========
Description: Ubuntu precise (development branch)
Release: 12.04

apt-cache policy xorg and apt-cache policy lightdm (I believe this might be a Lightdm bug too.)
==========================================================================
xorg:
  Installed: 1:7.6+12ubuntu1
  Candidate: 1:7.6+12ubuntu1
  Version table:
 *** 1:7.6+12ubuntu1 0
        500 http://gb.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages
        100 /var/lib/dpkg/status

lightdm:
  Installed: 1.2.0-0ubuntu2
  Candidate: 1.2.0-0ubuntu2
  Version table:
 *** 1.2.0-0ubuntu2 0
        500 http://gb.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: xorg 1:7.6+12ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-23.36-generic 3.2.14
Uname: Linux 3.2.0-23-generic x86_64
NonfreeKernelModules: wl
.tmp.unity.support.test.0:

ApportVersion: 2.0.1-0ubuntu1
Architecture: amd64
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: None
Date: Thu Apr 12 17:15:47 2012
DistUpgraded: Fresh install
DistroCodename: precise
DistroVariant: ubuntu
DkmsStatus:
 bcmwl, 5.100.82.38+bdcom, 3.2.0-17-generic, x86_64: installed
 bcmwl, 5.100.82.38+bdcom, 3.2.0-21-generic, x86_64: installed
 bcmwl, 5.100.82.38+bdcom, 3.2.0-22-generic, x86_64: installed
 bcmwl, 5.100.82.38+bdcom, 3.2.0-23-generic, x86_64: installed
ExtraDebuggingInterest: Yes, whatever it takes to get this fixed in Ubuntu
GraphicsCard:
 Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0116] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Acer Incorporated [ALI] Device [1025:0504]
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta amd64 (20120301)
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 8087:0024 Intel Corp. Integrated Rate Matching Hub
 Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
 Bus 001 Device 003: ID 1bcf:288a Sunplus Innovation Technology Inc.
MachineType: Acer Aspire 5750
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-23-generic root=UUID=294c451d-e2ed-4cfd-bbfe-9c443dd1a944 ro quiet splash acpi_backlight=vendor vt.handoff=7
SourcePackage: xorg
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/24/2011
dmi.bios.vendor: Acer
dmi.bios.version: V1.11
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: JE50_HR
dmi.board.vendor: Acer
dmi.board.version: Base Board Version
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: V1.11
dmi.modalias: dmi:bvnAcer:bvrV1.11:bd05/24/2011:svnAcer:pnAspire5750:pvrV1.11:rvnAcer:rnJE50_HR:rvrBaseBoardVersion:cvnAcer:ct10:cvrV1.11:
dmi.product.name: Aspire 5750
dmi.product.version: V1.11
dmi.sys.vendor: Acer
version.compiz: compiz 1:0.9.7.4-0ubuntu3
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.32-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 8.0.2-0ubuntu3
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 8.0.2-0ubuntu3
version.xserver-xorg-core: xserver-xorg-core 2:1.11.4-0ubuntu10
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