Cannot configure dual monitors

[Kerrick Staley <mail kerrickstaley com>]

Hello,
Adjusting the monitor resolution/layout settings in the Display panel has no effect on my laptop. In particular, switching layouts from mirrored to side-by-side doesn't work. I'd like to track down the cause of this bug.

I can configure the displays with 
$ xrandr --fb 3840x1080 --output DVI-I-1 --pos 0x0 --mode 1920x1080 --output LVDS-1 --pos 1920x0 --mode 1920x1080
but I have to run this command every time I boot the computer.

Running
$ gnome-control-center --verbose

doesn't indicate what the problem could be (there's a bunch of output about display modes when first loading the Display panel, but upon clicking "Apply", it doesn't print any additional information).

I would run gnome-settings-daemon with --debug and look at that output, but I cannot figure out how to stop and restart gnome-settings-daemon.

This laptop uses the Nouveau graphics driver and connects to the display over DVI. Another laptop with an Intel graphics driver, a VGA connection, and a different monitor works fine; both laptops run up-to-date versions of Gnome 3.2 and XOrg 1.12 on Arch Linux.

There is a bug report here: https://bugzilla.gnome.org/show_bug.cgi?id=667924

Thanks,
Kerrick Staley