Forwarding this bug from Ubuntu reporter (ml-bartschnet:
http://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/873718

[Problem]
The external monitor flashes between black screen (1-15 seconds) and desktop (500 ms - 2 seconds). The problem started with Ubuntu 11.04, prior versions (9.04 - 10.10) worked fine.   Still occurs in Precise as of 12/17.

[Original Description]
Notebook: Amilo Si2636, Intel GMA 3100
ATEN CS1784 KVM switch
HP LP2475w monitor
Cables: Si2636 -> HDMI-DVI-D -> ATEN CS1784 -> DVI-I/DVI-I -> HP LP2475w

The external monitor flashes between black screen (1-15 seconds) and desktop (500 ms - 2 seconds). The problem started with Ubuntu 11.04, prior versions (9.04 - 10.10) worked fine.

Currently I'm running the monitor directly attached via HP-HDMI-cable. HDMI-DVI-cables make things worse (also tried cables with gold-plated plugs). Mainboard (most current BIOS) and HDD of the Notebook have been replaced in April, RAM (3GB -> 4GB) at installation of Oneiric (64 bit) in November (I skipped 11.04 for permanent usage because of the video problems).

The Login-Screen is flickering and expanded to four tiles. Lower resolutions work stable for the Desktop, but about every third boot the Desktop is viewable but flickers maybe every 10 - 30 seconds until reboot. After screen lock, the monitor cannot sync anymore and displays "check cable".

The KVM-Switch stores the EDID of the monitor permanently (pressing "Numlock - d") and emulates monitor + USB in case K +V+M are switched to another port.

I tried Precise with no difference.

At 1680x1050 everything works fine, but at monitor-native FullHD-resolution (1920x1200) the HP LP2475w flickers. And there's no difference between direct HDMI-HDMI connection and KVM-Switch. The dmesg of Oneiric is attached, see 17:45 to 17:47 where I switched from 1680x1050 to 1920x1200 and back.

DistroRelease: Ubuntu 11.10
Package: xserver-xorg-video-intel 2:2.15.901-1ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-12.20-generic 3.0.4
Uname: Linux 3.0.0-12-generic x86_64
.tmp.unity.support.test.0:
 
ApportVersion: 1.23-0ubuntu3
Architecture: amd64
CasperVersion: 1.287
CompizPlugins: [core,bailer,detection,composite,opengl,compiztoolbox,decor,gnomecompat,grid,imgpng,mousepoll,move,place,regex,resize,session,snap,unitymtgrabhandles,vpswitch,wall,animation,expo,ezoom,fade,scale,unityshell,workarounds]
CompositorRunning: compiz
Date: Thu Oct 13 21:44:05 2011
DistUpgraded: Fresh install
DistroCodename: oneiric
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, whatever it takes to get this fixed in Ubuntu
GraphicsCard:
 Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller (primary) [8086:2a02] (rev 03) (prog-if 00 [VGA controller])
   Subsystem: Fujitsu Technology Solutions Device [1734:111f]
   Subsystem: Fujitsu Technology Solutions Device [1734:111f]
LiveMediaBuild: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
MachineType: FUJITSU SIEMENS AMILO Si 2636
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8ProcKernelCmdLine: file=/cdrom/preseed/hostname.seed boot=casper initrd=/casper/initrd.lz quiet splash -- maybe-ubiquity
SourcePackage: xserver-xorg-video-intel
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/08/2009
dmi.bios.vendor: Phoenix
dmi.bios.version: 1.0H-1471-0012
dmi.board.name: MR030___
dmi.board.vendor: FUJITSU SIEMENS
dmi.board.version: 8r7b19507
dmi.chassis.type: 10
dmi.chassis.vendor: FUJITSU SIEMENS
dmi.chassis.version: Version 1.0
dmi.modalias: dmi:bvnPhoenix:bvr1.0H-1471-0012:bd05/08/2009:svnFUJITSUSIEMENS:pnAMILOSi2636:pvrREFERENCE:rvnFUJITSUSIEMENS:rnMR030___:rvr8r7b19507:cvnFUJITSUSIEMENS:ct10:cvrVersion1.0:
dmi.product.name: AMILO Si 2636
dmi.product.version: REFERENCE
dmi.sys.vendor: FUJITSU SIEMENS
version.compiz: compiz 1:0.9.6+bzr20110929-0ubuntu3
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.26-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 7.11-0ubuntu3
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.11-0ubuntu3
version.xserver-xorg: xserver-xorg 1:7.6+7ubuntu7
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.6.0-1ubuntu13
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.99~git20110811.g93fc084-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.15.901-1ubuntu2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20110411+8378443-1