Wrong screen resolution in Ubuntu (nvidia proprietary driver)

Question

I have a BenQ GW2400 and a Geforce FX5200. I run Ubuntu Karmic 9.10, and have the newest proprietary Nvidia driver installed. The GW2400 supports 1920x1200, but I can only select 1600x1200 from the nvidia x server program. Does anyone know how to enable higher resolutions? I've read something about adding custom modelines in /etc/X11/xorg.conf and so on, but I don't know if that applies to Karmic.

Thanks.

Update

I tried all of the approaches in the answers below, with no success. Everything got sorted out as soon as I upgraded to Ubuntu 10.04 (even fixed my half-broken WLAN connection). Anyways, thanks for answering guys :)

Solution

First backup your xorg.conf file:

sudo cp /etc/X11/xorg.conf /etc/X11/xorg.conf.backup

The default color depth is 24 I believe, so in /etc/X11/xorg.conf add this:

Section "Screen"
    SubSection     "Display"
        Depth       24
        Modes      "1920x1200" "1600x1200" "1024x768" "800x600" "640x480"
    EndSubSection
EndSection

restart the X server for changes to take effect. You can use sudo /etc/init.d/gdm restart.

This may also come in handy, HOWTO: change resolution/refresh rate in Xorg.

Comments

[quack quixote]

i believe stock ubuntu 9.10 doesn't actually provide an xorg.conf (or it's empty) -- it allows X to detect everything on startup. you can add anything you need to one, so this is still the proper procedure, but i think you'll need to add the entire Screen section (that "Display" is a "SubSection" of).

[Nerdfest]

Yeah, and ctrl-alt-BackSpace doesn't work by default anymore either.

[John T]

Oh gosh, fixed again :)

[quack quixote]

sudo aptitude install dontzap should reinstate the old Ctrl-Alt-Backspace behavior. er... oops, n'mind, that's jaunty only: in karmic, see this to reenable via XKB: wiki.ubuntu.com/X/Config/DontZap