Comment 13 for bug 158343

@Leann Ogasawara
I've just tested Hardy Alpha 3 and the bug still exists, but it happens less often. I used the live cd for 50 minutes and the spontaneous change in brightness happened just once (around 48th minute).
Let me say once again what happens on my machine (I've said it somewhere else...).
 * "unwanted changes" - brightness _always_ changes to the value of "Set display brightness to:" slider in "On AC Power" tab in gnome-power-preferences. If current brightness == the value of this slider, then brightness doesn't change.
 * "unwanted changes are triggered by"
 ** opening of gnome-power-preferences (instant change of brightness) - both gutsy and hardy
 ** spontaneous change (user doesn't have to do anything). every XXX seconds in gutsy, once in 50 minutes in hardy

The workaround is to use that slider for adjusting the brightness... I've been doing it ever since gutsy was released and it's not that annoying.