2008.1 Eee External Monitor

From Mandriva Community Wiki

Many people use external monitors with their Eee PCs. You may notice that by default, when you connect an external monitor, the external and internal monitors use clone mode: the display is set to the native size of the biggest display (usually the external one), and the Eee's internal display just shows a copy of the top left hand corner of what's on the external display.

This isn't the most useful set up for most people! Usually, you'd want to have the two displays act as one big screen, and let you move the mouse from one to the other. Fortunately, this isn't too hard with Mandriva Linux 2008 Spring.

The hardest part comes first. You need to edit the file /etc/X11/xorg.conf. For instructions on how to edit system files like this, see this page. Near the bottom, you will see a section like this:

Section "Screen"
    Identifier "screen1"
    Device "device1"
    Monitor "monitor1"
    DefaultColorDepth 16
    
    Subsection "Display"
        Depth 8
        Modes "800x480" "640x480"
    EndSubsection
    
    Subsection "Display"
        Depth 15
        Modes "800x480" "640x480"
    EndSubsection
    
    Subsection "Display"
        Depth 16
        Modes "800x480" "640x480"
    EndSubsection
    
    Subsection "Display"
        Depth 24
        Modes "800x480" "640x480"
    EndSubsection
EndSection

You need to change the lines in this section that look like this:

        Modes "800x480" "640x480"

What you change them to depends on the resolution of the external monitor. If you want the monitors to be side by side - so if you move the mouse pointer off one side of one monitor, it goes onto the other - you need to add 800 to the horizontal resolution of the external monitor (800 being the horizontal resolution of the internal monitor). So if your external monitor uses 1024x768 resolution, you add 800 to 1024, and get 1824. Then you take whichever of the two monitors' vertical resolutions is the highest: in our example, that's the external monitor's 768 (which is bigger than the internal monitor's 480). So in this example, the numbers we get are 1824 768.

If you want the monitors to be one above the other - so when you move the mouse pointer off the bottom of one monitor, it moves to the top of the other - you do much the same, except you take the largest horizontal resolution and combine the vertical resolutions. So with the same example external monitor, you would get 1024 1248 - 1024 is the biggest horizontal resolution, and 1248 is 480 plus 768.

Whatever the numbers you end up with, you use them in the xorg.conf file. You replace the:

        Modes "800x480" "640x480"

lines with lines like this:

        Virtual 1824 768

where the numbers are the numbers you just worked out. Change all four of the lines like this. This tells the graphics card driver to create one big 'screen' that's big enough to fit both your monitors combined.

Once this is done, you must reboot the system (or just restart X). Now, if you use KDE, you can use the krandrtray tool to mostly set up the monitors. It should already be running: in the notification area of your panel (next to the clock) you should see an icon that looks like a blue screen with an arrow in it. Right click on this, and uncheck the Unify Outputs box if it is checked. Then right click on it again, highlight LVDS, and check that it is set to the correct resolution for the Eee's internal monitor - 800x480. Now right click on it again, highlight VGA, and select the correct resolution for your external monitor. To actually set the monitors to be used separately, though, you must use the command line xrandr tool. If the internal monitor is placed to the right of the external monitor, run:

xrandr --output LVDS --right-of VGA

If it's to the left, run:

xrandr --output LVDS --left-of VGA

If it's above the external monitor, run:

xrandr --output LVDS --above VGA

And if it's below it, run:

xrandr --output LVDS --below VGA

And the layout should now be correct.