LCD backlight stays off after resume

The LCD backlight often stays off after resume and less often after opening the lid when it has been closed for a long time. The "vbetools dmps on", brightness controls, switching virtual consoles do not have any effect. Shutdown and restart usually don't fix the problem either. The only reliable way to get the backlight on again is to disconnect power, take out the battery, press the power button for a few seconds, put the battery back and then switch the computer on again. I found that solution at one of the forums.

The very reliable way to reproduce the problem is:

1. Set the "When laptop lid is closed" action in the On AC Power tab of the Power Management Preferences dialogue to Blank Screen, set that action to Suspend in the On Battery Power tab.
2. Close the lid when connected to the power supply.
3. Disconnect the power supply: laptop goes to the sleep mode.
4. Open the lid: Laptop wakes up, but the backlight stays off.

The closest bug report I found is:
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/580225

I am using Dell XPS m1330 with Intel integrated graphics (GM965).

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: linux-image-2.6.32-22-generic 2.6.32-22.36
Regression: Yes
Reproducible: Yes
ProcVersionSignature: Ubuntu 2.6.32-22.36-generic 2.6.32.11+drm33.2
Uname: Linux 2.6.32-22-generic i686
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.21.
Architecture: i386
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: vladimir 1641 F.... pulseaudio
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xfe9fc000 irq 21'
   Mixer name : 'Silicon Image SiI1392 HDMI'
   Components : 'HDA:83847616,1028020a,00100201 HDA:10951392,1028020a,00100000'
   Controls : 32
   Simple ctrls : 19
Date: Sat Jun 19 20:50:16 2010
HibernationDevice: RESUME=UUID=1117921a-2c72-45aa-9dec-44c330fc96c8
MachineType: Dell Inc. XPS M1330
ProcCmdLine: root=UUID=e8743d05-3772-460d-92c7-dddbdcf90c0e ro quiet splash
ProcEnviron:
 PATH=(custom, user)
 LANG=en_AU.utf8
 SHELL=/bin/bash
RelatedPackageVersions: linux-firmware 1.34
SourcePackage: linux
UserAsoundrc:
 # ALSA library configuration file

 # Include settings that are under the control of asoundconf(1).
 # (To disable these settings, comment out this line.)
 </home/vladimir/.asoundrc.asoundconf>
WpaSupplicantLog:

dmi.bios.date: 04/21/2008
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A10
dmi.board.name: 0N6705
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA10:bd04/21/2008:svnDellInc.:pnXPSM1330:pvr:rvnDellInc.:rn0N6705:rvr:cvnDellInc.:ct8:cvr:
dmi.product.name: XPS M1330
dmi.sys.vendor: Dell Inc.