Creating a virtual X11 output with Nvidia driver

Question

I'm attempting to follow this guide to extend the desktop on computer A to computer B by creating a virtual output on computer A and using vnc to display the virtual output on computer B.

The problem I'm having is that the Nvidia driver does not allow screens that are not connected to be used neither does it create any virtual outputs.

Is it possible to create virtual outputs with the Nvidia (or even Nouveau) drivers?

Answer 1

I'm using this on a daily basis. You need an xorg.conf file, in your Device section you need the following:

Option      "nopowerconnectorcheck"
Option      "ExactModeTimingsDVI" "ON"

Then in your Monitor section place your HorizSync, VertRefresh, and ModeLine Finally in your Screen section add this:

Option "AllowEmptyInitialConfiguration" "True"
Option "ConnectedMonitor" "DFP"
Option "UseDisplayDevice" "DFP-0"
Option "ModeValidation" "AllowNonEdidModes"
SubSection     "Display"
        Depth       24
        Modes       "<Resolution and Refresh from your modeline>"
EndSubSection

What this does is tells the Nvidia driver that there is a monitor attached, and gives it the information required to start drawing to the frame buffer. No monitor required. I do recommend using x11vnc to do your viewing because it polls the screen and is much more responsive to screen changes than any other linux vncserver.