Optimal configuration

2010 October 21

Dual head with rotation with an nvidia graphics card on Debian Linux

Filed under: dualhead,linux,nouveau,nvidia,x11,xorg — Eric Fraga @ 16:16

I recently acquired a second display for my main system. I have been using a dual head system for a while but I now had two monitors which could change orientation. I decided it might be quite nice to have both of them in a portrait orientation as the majority of my work is either writing or coding. I would rather have more lines in my Emacs windows than more columns. I usually have auto-fill turned on and I also typically try to ensure that my coding limits itself to 80-100 columns at most.

However, when using the nv driver that is available in the Xorg system, I found that I could get dual head support but I could not manage to get xrandr to rotate the orientation for either screen. After a while searching, and trying a few of the options, it became clear to me that I was not going to manage to get nv to do what I wanted. At this point, I decided to explore the nouveau driver as I did not want to resort to the non-free nvidia driver that was also available.

nouveau seemed, from the documentation, to provide the features I wanted. However, this didn’t work at all out of the box, generating errors about drm cards, errors like this:

drmOpenDevice: node name is /dev/dri/card0
drmOpenByBusid: drmOpenMinor returns -1

After some searching on the web, I came across this page which pointed me in the right direction. It suggests updating libdrm but I already had the most up to date version. It also suggests, however, removing any traces of the proprietary nvidia driver. This did the trick! I did have to reboot after purging all evidence of that driver, and kernel modules etc, but I now have a dual rotated head system which is a joy to use!

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