11.10 thinks DVI video card output is HDMI

[Nick Payne]

I installed 11.10 amd64 on a machine with a dual head nVidia card (shown by lspci as "nVidia Corporation G92 [GeForce GTS 250] rev a2") with twin DVI outputs and a primary 30" monitor and secondary 23" monitor in portrait orientation, both connected via DVI. After 11.10 install completed, the right-hand 23" monitor remains blank and in power save, although when I open System Settings / Displays, both monitors appear there with the initial display configuration showing as mirrored displays at 1152x864 resolution. Un-mirroring the displays and setting each display to its native resolution and orientation still has the LH monitor blank. I think the problem is that the 23" monitor is being incorrectly detected as being connected via HDMI, as when I run xrandr in a terminal it shows

nick@ubuntu1110:~$ xrandr
Screen 0: minimum 320 x 200, current 3640 x 1920, maximum 8192 x 8192
DVI-I-1 connected 2560x1600+0+0 (normal left inverted right x axis y axis) 641mm x 401mm
2560x1600 60.0*+
1920x1440 60.0
1920x1200 59.9
1600x1200 60.0
1280x1024 75.0 60.0
1280x800 59.8
1152x864 75.0
1024x768 75.1 60.0
800x600 75.0 60.3
640x480 75.0 60.0
720x400 70.1
HDMI-1 connected 1080x1920+2560+0 right (normal left inverted right x axis y axis) 509mm x 286mm
1920x1080 60.0*+
1280x1024 75.0 60.0
1152x864 75.0
1024x768 75.1 60.0
800x600 75.0 60.3
640x480 75.0 60.0
720x400 70.1

My primary OS on this machine is Ubuntu 10.04. If I boot into that both monitors work fine, though there I'm using the nVidia closed source driver. I'd like to try getting 11.10 to work with the nouveau driver, so that I don't have to configure separate X screens to run one monitor in portrait orientation.

Is there any way I can use xrandr or something else to tell 11.10 that the 23" monitor is connected using DVI?