Bitfever

Don't you just hate it?

Although you have turned off the "Lower display birghtness…" setting for the power adapter in the Energy Savings panel it just gets ignored. Some searching on the Apple Knowledge Base turns up this Article wich basically states: "We know it is a problem, but we did not care to fix it."

Here is a simple script you can run to stop you display from misbehaving:

[code lang="shell-unix-generic"] sudo pmset -c halfdim 1 sudo pmset -c halfdim 0 [/code]

It turns out, that turning the setting off and on again fixes the issue (at least till the next time you disconnect the power supply or put your mac to sleep.