I just set up a new Arch with Gnome 3.2. Until now, everything seems to work fine, except for the brightness adjustment. When I try to adjust the brightness from within the Gnome settings or with Fn+☼↑, the screen flickers for some seconds and afterwards the brightness stays the same (Fn variant) or has changed (Gnome settings). It seems like some other part of the system insists on keeping the brightness as is, there is a fight and this other part wins.
The Hardware is a Samsung N130 Netbook with an Intel 945GME graphics controller.
update: The culprit of this manifests itself as this line in
samsung_laptop: SABI set command 0x01 failed with completion flag 0xaa and data 0xff
Some research led to this, which says that a patch for the problem is on its way into the 3.2 kernel.