Comment 8 for bug 842459

I can confirm this on Thinkpad T410 with ubuntu 11.10. The way it's happening with me is:

1. Set manually the preferred brightness.
2. Wait some time (usually about 3 secs).
3. press a key or move mouse.
4. Screen goes to full brightness.

I have the power plugged in. This is naturally very annoying. I disabled "Dim screen to save power" checkbox in "Screen settings" to avoid any possible "automatic adjustments" (that was the only related adjustment I found) and it still brings up the brightness to max.