Multiple Displays in Ubuntu 12.04

Our Xubuntu 12.04 install does not include any tools or options for enabling a secondary display as an extension of the desktop rather than a mirror.

Systems with NVidia GPUs

Multiple displays can be configured using the NVidia X Server Settings tool found in the System submenu.

The NVidia drivers and settings packages will need to have been installed using the Additional Drivers tool in the Settings submenu.

Systems with integrated/other video controllers

The ability to configure multiple displays can be added by the arandr package.

First, make sure the additional display to be used is connected to the system and turned on.

Open a terminal window and enter the following commands:

sudo apt-get install arandr
arandr

This will install and open the Screen Layout Editor.

To configure an extended display, first check the Outputs menu and make sure that all displays to be used are marked as Active. For a laptop the additional screen will typically be listed as VGA-0 or VGA-1 while the laptop's own screen will be LVDS-0.

Once the desired displays are marked as active their labeled representations will appear in the main layout area of the Screen Layout Editor. Arrange these representations to match the physical arrangement of the screens (or however the user would like their arrangement to be treated). Once the displays are arranged as desired just click the checkmark button above the top-left corner of the main layout area to apply the settings.

Note that the system will not intelligently reconfigure the screen if the second display is detached while the system is still running; it will revert to a single display if the system is rebooted after the secondary display has been detached though. Additionally, in my testing (Psullivan) these settings are not preserved between reboots even if all displays remain connected, but this testing was conducted on a system which also has the NVidia X Server Settings installed, which may be overriding the configuration.