I am trying to find the maximum supported resolution of my video card by using xrandr. My card is an NVidia GeForce Go 7300 (in a laptop). The official documentation does not list specific resolutions that are supported. My laptop display is detected as "AUO" in the NVidia X Server Settings dialog (Ubuntu 10.04 amd64) and has a native resolution of 1280x800. However, I would like to know what is the maximum resolution that I could use on a display with the VGA adapter irrespective of whether the laptop's display is on. This is what I get from xrandr:

Screen 0: minimum 512 x 384, current 1280 x 800, maximum 2304 x 864
default connected 1280x800+0+0 0mm x 0mm
1280x800 50.0* 51.0 56.0 52.0
1024x768 52.0 50.0
680x384 53.0 54.0
512x384 55.0
2304x800 56.0
1360x800 51.0
1280x864 52.0

I am guessing the maximum width of 2304 would be for using TwinView with the laptop's 1280-width display next to a 1024 CRT or similar. Surely these cannot be the only supported resolutions. I would like to use a LCD display of width somewhere around 1600 pixels (in particular while turning off the laptop's screen so as to use the external LCD as the primary display) if possible. Any help would be appreciated.

There are two programs supplied with the propriety driver. nvidia-settings works great for configuring twin-view setups.

Please no spam here. Take it elsewhere. Thank you.

Yes the nvidia-settings works very well. I usually use it for hooking up a projector. But my concern is that it won't let me go beyond 1024x768 for the external display because it always assumes the laptop display is on (otherwise anything more than 1024 would exceed 1280+1024=2304). Also I am concerned whether this card cannot support any height greater than 864. I would find that hard to believe as many cards from circa 1998 can handle e.g. 1280x1024 with no problem.

Examine the /var/log/xorg.0.log file. It could be that other resolutions are tried but don't work. I doubt it for the proprietary driver however if the card supports it.

You might try using the "gtf" program to generate a custom mode line. I used it when I just got a Laptop with 16x10 display resolution which wasn't supported at that time. You will want to check that you have sane values for HorizSync and VertRefresh in the Monitor section.

gtf <xres> <yres> <freq> -x

e.g. gtf 1440 900 60 -x

Sorry for the delay. I kind of forgot about this...Adding extra modelines to my xorg.conf doesn't seem to change anything. Am I wrong, but would this just be forcing my laptop display into an impossible resolution if I list this in the "Monitor" section?

In 'nvidia-settings', if you click on the monitor, like DFP-1, it will tell you the native resolution, which is also the maximum resolution. The nivida drivers use the EDID given by the monitor to set resolutions, and you should only override this if you have proof or a manual that say otherwise, because you can damage the screen if you try to run at higher resolutions.