Libretto Dual Head

A dual-head display on a desktop computer requires either two graphics cards or a special graphics card with two outputs. One the other hand, notebook computers usually contain a graphics chip that can drive an external monitor and the internal LCD at the same time, so a dual-head display can be achieved with no extra hardware.

Here's what you'll need for dual-head display with your ToshibaLibretto under Linux:

• Libretto L5 (has ATI graphics chip) with stock XFree86 driver (4.2.1 or better), or Libretto L1-L3 (S3 graphics chip) with [Duoview driver].
• ToshibaAcpiDriver (for enabling the external video)
• XFree86 4.2.1 or better
• optional: dual-head aware desktop (for example, KDE 3.1)

An example X configuration file is available [1]. (Warning: the example sets keyboard layout to Dvorak, which you probably don't want.) The main points of the configuration are:

• make two Device sections, setting BusID, Screen, and CrtScreen attributes appropriately
• make two Monitor sections, LCD and external
• make two Screen sections, each linking one device and one monitor
• in the ServerLayout section, specify the relation of the screens and (optionally) set the xinerama flag

If you are having X problems, check the log file (/var/log/XFree86.0.log) for clues. Search for "(WW)" and "(EE)" in the file to quickly locate warnings and errors.

Use the following command to enable the external display. It seems like this must be done before starting the X server for dual-head to work.

echo "crt_out:1" > /proc/acpi/toshiba/video

Xinerama is a dual-head mode were you can naturally drag windows from one display to the other. If xinerama is not enabled, each display will act as a separate desktop. In that case, you can select which display an application will appear in by setting the X DISPLAY variable to ":0.0" or ":0.1" when launching the application.