* Robert Schweikert email@example.com [2012-01-21 03:11]:
Finally managed to convince myself that I needed two monitors. Now with two wonderful 23" displays sitting on my desk, I have one problem. The display behaves as if they are mirrors of each other.
Now I am not certain if this is a configuration in X11 or in the Desktop Environment.
it depends, you can statically configure your monitors in xorg.conf/xorg.conf.d but usually this is done dynamically via the RandR extension which allows for hotplugging. DE's usually provide frontends for the latter, unfortunately the one in Xfce is very rudimentary and does not support switching from the default cloned mode to different layouts. So you have to use the xrandr utility from the command line to configure the desired layout, first you need to query the current configuration with:
$ xrandr --query
which will output something like this:
DVI-D-0 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 509mm x 286mm 1920x1080 60.0*+ 1600x1200 60.0 1680x1050 60.0 1400x1050 60.0 1280x1024 75.0 60.0 1440x900 59.9 1280x960 60.0 1152x864 75.0 1024x768 75.1 70.1 60.0 832x624 74.6 800x600 72.2 75.0 60.3 56.2 640x480 72.8 75.0 66.7 60.0 720x400 70.1 DVI-D-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 509mm x 286mm 1920x1080 60.0*+ 1600x1200 60.0 1680x1050 60.0 1400x1050 60.0 1280x1024 75.0 60.0 1440x900 59.9 1280x960 60.0 1152x864 75.0 1024x768 75.1 70.1 60.0 832x624 74.6 800x600 72.2 75.0 60.3 56.2 640x480 72.8 75.0 66.7 60.0 720x400 70.1
The above tells you that you have two screens "DVI-D-0" and "DVI-D-1" (the names and modes will likely differ on your box, so substitute your display names accordingly in the following commands), in order to place "DVI-D-1" to the right of "DVI-D-0" execute the following:
xrandr --output DVI-D-0 --auto --output DVI-D-1 --auto --right-of DVI-D-0
In case "DVI-D-1" is to the left of "DVI-D-0" replace "--right-of" with "--left-of" in the above command (for the details see man xrandr). IIRC once you have configured this xfce4-settings should remember that and restore it on the next login.
I have an Nvidia card, but am not running the proprietary driver, i.e. using nouveau. Before I run off installing the proprietary driver and setup utility (and I guess this tells me that it's really an X11 setting?) I am hoping that someone can tell me how to get things working, i.e. displays behave independently, without the proprietary Nvidia driver.
Note that in contrast to the nouveau driver the proprietary Nvidia driver does not support RandR and provides its own configuration utility.