I do not want my laptop to change brightness when my laptop power is plugged in or unplugged. I set my brightness based on how bright my surroundings are. If I am in a dark room, I set my brightness very low and when I plug my laptop in the brightness gets set to maximum which feels like sticking my eyes in boiling lava.
In System Settings ▸ Brightness and Lock the Dim screen to save power checkbox is unchecked.
My laptop is an HP Mini 110
In case it is an acpi issue I have put my acpi-support file here
[link removed because it expired]