My laptop (Dell Studio 1535) is able to control display brightness by itself - it remembers brightness settings for states running on battery/AC power. When I disconnect AC power, it dims display automaticaly to state where I left it on battery, if I connect it again, it adjust the brightness where I left it on AC power.
Problem is that ubuntu messes it up - it tends to adjust the brightness by itself then and it always switches brightness in a wrong way, not to the level I left it.
Brightness is adjusted even on boot - during xsplash, before login is shown, it sets brightness to maximum, when I dim it e.g. to the minimum and then log in, it is again adjusted to the maximum.
There is a way to turn software dimming off in gnome-power-manager, but it has no effect during the boot and after loging in, it is only respected when I connect/disconnect AC when already logged in.
As software dimming is absolutely useless when laptop itself can control it, there really should be some kind of laptops "whitelist" for which it would be turned off by default and/or there should be an option to turn it off completly even during the boot.
I've removed the ubuntu-