Using Jaunty Jackalope, kubuntu, I'm experiencing odd errors with the laptop brightness display.
When the screensaver is enabled, and by this I mean it set to start up in X amount of minutes, my display will dim to the lowest or near-lowest setting. Every time I try to brighten it by either setting in KDE or by my laptop FN keys it will convert back to the lowest setting. Interestingly, the brightness sliders in the powersaving programs or the battery widget remain at the highest setting.
OK, so the workaround for that was to simply disable the screensaver. However, I soon discovered that OpenGL games such as etracer and neverball would also dim the display upon starting (or even attempting to start; this occured when there was an error with an openSDL package that prevented the game from starting--but that's another separate issue I had dealt with). VLC and Dragon Player both dim the backlight upon loading a movie, as well.
Laptop is a Acer Aspire 7720Z, graphics card is Intel GM965 / X3100. Hopefully this report is adequate, I don't know what else to add.
To clarify on the screensaver, I mean that if it's enabled at all to start up in the specified amount of idle time, my laptop brightness setting converts back to the dimmest in a matter of seconds after I set it brighter, either through sliders or Fn keys.
I figured out the solution to this because a post somewhere (ubuntu forums?) mentioned this for a past release or something, but alas I cannot find it again.