USB read/write errors turns monitor to text only display

[Problem] USB external disk read/writes which the systems reports by turning the monitor to text only, but X continues to work. The main laptop screen will suddenly switch to "black screen with text (the error message), a blinking cursor and a working mouse pointer", while the external monitor continues to work ok. Please also refer to video, as it is slightly difficult to explain in writing only: http://ubuntuone.com/4co3KnLvJXAyryLT3FKWbZ

The X.org log gets flooded with the below when it occurs:
(WW) intel(0): first get vblank counter failed: Invalid argument

WORKAROUND: Disconnect the external monitor.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: xorg 1:7.7+1ubuntu4
ProcVersionSignature: Ubuntu 3.5.0-18.29-generic 3.5.7
Uname: Linux 3.5.0-18-generic x86_64
.tmp.unity.support.test.0:

ApportVersion: 2.6.1-0ubuntu6
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
Date: Sun Nov 11 10:24:12 2012
DistUpgraded: Fresh install
DistroCodename: quantal
DistroVariant: ubuntu
DkmsStatus: vboxhost, 4.2.4, 3.5.0-18-generic, x86_64: installed
ExtraDebuggingInterest: Yes, if not too technical
GraphicsCard:
 Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Lenovo Device [17aa:21f6]
InstallationDate: Installed on 2012-10-20 (21 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
MachineType: LENOVO 2359CTO
MarkForUpload: True
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.5.0-18-generic root=UUID=58df012a-941b-41a5-81c5-81341f040158 ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/29/2012
dmi.bios.vendor: LENOVO
dmi.bios.version: G4ET37WW (1.12 )
dmi.board.asset.tag: Not Available
dmi.board.name: 2359CTO
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvrG4ET37WW(1.12):bd05/29/2012:svnLENOVO:pn2359CTO:pvrThinkPadT530:rvnLENOVO:rn2359CTO:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 2359CTO
dmi.product.version: ThinkPad T530
dmi.sys.vendor: LENOVO
version.compiz: compiz 1:0.9.8.4+bzr3407-0ubuntu1
version.ia32-libs: ia32-libs 20090808ubuntu36
version.libdrm2: libdrm2 2.4.39-0ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 9.0-0ubuntu1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 9.0-0ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.13.0-0ubuntu6
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.3-0ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.99.99~git20120913.8637f772-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.20.9-0ubuntu2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.2-0ubuntu3