LinuxQuestions.org - Lenovo Thinkpad T61 brightness inconsistency

I am running Kubuntu 8.04.1 on my Lenovo ThinkPad T61, and I have been having inconsistent screen brightness.

I set the brightness on my laptop to 100%, then I play a video and the screen brightness drops to 20%. When I press the brightness buttons, KDE thinks that it is still at 100%.

If I lower the brightness, it jumps up to that high level (say like 90%) and then I can push it back up to 100%.

While playing video, about every 30 seconds, the brightness drops back down to 20%, and it continues to do this no matter if I toggle-raise it back up.

Any time I do anything that affects the video display, such as a screen saver, the brightness also drops.

It started about 2 weeks ago (mid July 2008 ).

Hardware specs:
Video card: Intel GMA X3100 GM965

My video resolution is 1280x800. Here is my xorg.conf:

Code:

# xorg.conf (X.Org X Window System server configuration file)

#

# This file was generated by dexconf, the Debian X Configuration tool, using

# values from the debconf database.

#

# Edit this file with caution, and see the xorg.conf manual page.

# (Type "man xorg.conf" at the shell prompt.)

#

# This file is automatically updated on xserver-xorg package upgrades *only*

# if it has not been modified since the last upgrade of the xserver-xorg

# package.

#

# If you have edited this file but would like it to be automatically updated

# again, run the following command:

#  sudo dpkg-reconfigure -phigh xserver-xorg



Section "InputDevice"

  Identifier  "Generic Keyboard"

  Driver    "kbd"

  Option    "XkbRules"  "xorg"

  Option    "XkbModel"  "pc105"

  Option    "XkbLayout" "us"

EndSection



Section "InputDevice"

  Identifier  "Configured Mouse"

  Driver    "mouse"

  Option    "CorePointer"

EndSection



Section "InputDevice"

  Identifier  "Synaptics Touchpad"

  Driver    "synaptics"

  Option    "SendCoreEvents"  "true"

  Option    "Device"    "/dev/psaux"

  Option    "Protocol"    "auto-dev"

  Option    "HorizEdgeScroll" "0"

EndSection



Section "Device"

  Identifier  "Configured Video Device"

EndSection



Section "Monitor"

  Identifier  "Configured Monitor"

EndSection



Section "Screen"

  Identifier  "Default Screen"

  Monitor  "Configured Monitor"

  Device    "Configured Video Device"

EndSection



Section "ServerLayout"

  Identifier  "Default Layout"

  Screen    "Default Screen"

  InputDevice "Synaptics Touchpad"

EndSection