Monday, August 24, 2015

Enabling correct monitor drivers on Ubuntu 14.04 LTS

Having recently installed Ubuntu 14.04 LTS on a new PC, I had some troubles configuring the display to operate correctly with a Dell 24" monitor: specifically, the monitor aspect ratio of 1920x1200 (16:10) didn't seem to be supported by the default install from the Live CD. In fact it was more than a little unstable (to say the least: for example, attempting to change the display aspect ratio rendered the display unusable several times, necessitating a complete reinstall to recover).

This appeared to be a missing driver issue, but it was difficult to find out what drivers were needed. Searching on the web for the specific problem was rather fruitless, and the many suggestions to look at xrand (for example https://wiki.ubuntu.com/X/Config/Resolution) didn't work for me either. In the end I stumbled across a post which suggested using the command:

ubuntu-drivers devices

from a terminal, which shows all devices which need drivers, and which packages apply to them. For example for my system the output looks like:

== /sys/devices/pci0000:00/0000:00:02.0/0000:03:00.0 ==
vendor  : NVIDIA Corporation
modalias : pci:v000010DEd000013BAsv000010DEsd00001097bc03sc00i00
driver  : nvidia-346-updates - distro non-free
driver  : nvidia-346 - third-party free
driver  : nvidia-340 - third-party free
driver  : nvidia-352 - third-party free
driver  : xserver-xorg-video-nouveau - distro free builtin
driver  : nvidia-349 - third-party non-free
driver  : nvidia-355 - third-party free recommended
driver  : nvidia-340-updates - distro non-free

When I ran this it marked 'nvidia-349' as the recommended driver (nb the output above is from a subsequent run of ubuntu-drivers and doesn't show the mark). This was easily installed using:

apt-get install nvidia-349

and appeared to solve my issues. Unfortunately I haven't been able to find the post again that originally suggested this, however if you are experiencing similar resolution issues then it might be worth a try before grappling with xrand.

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