can't output to external monitor via VGA port

[TienFu Chen]

system: Asus 1015PX, 201103-7458

Symptom: external monitor is blank when I plugged in the vga cable.

In gnome-control-center, only 1920x1080 can't output to external VGA in the extended mode, other modes work.
1024x768 and 800x600 have all rotation options(Normal,180 degrees, clockwise and counterclockwise), but for 1920x1080, 1440x900, 1280x800, 1151x864, they only have clockwise and counterclockwise options.

Monitor is Acer S243HL, http://us.acer.com/ac/en/US/content/model/ET.FS3LP.001

-------------------------------------------
ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-image-3.2.0-23-generic 3.2.0-23.36
ProcVersionSignature: Ubuntu 3.2.0-23.36-generic 3.2.14
Uname: Linux 3.2.0-23-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
AplayDevices:
 **** List of PLAYBACK Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC269VB Analog [ALC269VB Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
ApportVersion: 2.0.1-0ubuntu5
Architecture: amd64
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC269VB Analog [ALC269VB Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: ubuntu 1692 F.... pulseaudio
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf7cf8000 irq 45'
   Mixer name : 'Realtek ALC269VB'
   Components : 'HDA:10ec0269,10438437,00100100'
   Controls : 12
   Simple ctrls : 7
Date: Wed May 16 05:07:02 2012
HibernationDevice: RESUME=UUID=e272094c-e920-432a-81a3-27a1de1930e1
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MachineType: ASUSTeK Computer INC. 1015PX
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-23-generic root=UUID=9a314a8b-9a61-4569-ad9b-082da1abcb7f ro quiet splash initcall_debug vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.2.0-23-generic N/A
 linux-backports-modules-3.2.0-23-generic N/A
 linux-firmware 1.79
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/03/2010
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1001
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: 1015PE
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: x.xx
dmi.chassis.asset.tag: 0x00000000
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK Computer INC.
dmi.chassis.version: x.x
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr1001:bd12/03/2010:svnASUSTeKComputerINC.:pn1015PX:pvrx.x:rvnASUSTeKComputerINC.:rn1015PE:rvrx.xx:cvnASUSTeKComputerINC.:ct10:cvrx.x:
dmi.product.name: 1015PX
dmi.product.version: x.x
dmi.sys.vendor: ASUSTeK Computer INC.

[Anthony Wong (anthonywong)]

This bug has its origin from bug 830949. External monitor doesn't work since the combined resolution is too big.

@Tim
After you plug in the VGA cable, except the external monitor being blank, what other problem do you see? Can you still use the internal LCD normally?

[kaxing (kaxing)]

@Anthony Wong

I don't have this system anymore, and also I can't change the status of this bug, please update it if you can.

if someone have this system, please feel free to verify this issue.