On Linux, when laptop is connected to AC power (or disconnected) the screen brightness changes. How can I avoid it?
It's not always brighter with AC. If I increase brightness on battery and then plug in, the screen gets darker. Apparently the last value on AC is restored. So the system remembers two values and switches between them. I'd rather have only one.
I don't know if it is desktop specific. I've had this problem on both XFCE and MATE.
When searching for an answer I've only found a similar request for Linux Mint, and the same question on SU but for Windows.