Comment 9 for bug 104745

I also can report this problem under Kubuntu 8.04 (hardy).

When I first installed the system, the monitor couldn't be automatically detected, I had to fix this using xfailsafedialog.

Originally, on a screen brightness change, the top-left quarter of the screen was magnified to fill the whole screen, you could restore the desktop either by changing virtual terminal, or changing to another mode in X, and back to the wanted mode. I then added the option "CyberStretch" to the graphic card section of xorg.conf - after this instead of magnifying the screen, the display was corrupted (In recent testing I noticed that a part of the screen near the left is magnified by about 1.5 times, and then shown corrupted on the monitor - any text etc. is not recogniseable as such. - The corruption is much worse than what was shown above.), however you could restore the desktop as before.

When the screen is locked (In my setup the screen just goes black, a small unlock dialog is shown in the centre of the screen), and the brightness is changed (as happens when closing the laptop lid), then the screen shows only black. This can be fixed in the same way again.

Also: If the screen brightness is set to the same brightness it currently is, i.e. by using
echo 'brightness: X' > /proc/acpi/toshiba/lcd
then nothing happens. (I doubt this is important, since the acpi software probably checks if the wanted brightness equals the current brightness before doing anything else.)

Taking a screenshot internally (i.e. using Ksnapshot, run using the PrintScreen button), results in an image of what should be shown (the uncorrupted image).