Working Dual Screen for my Aspire One with Fedora 10

Posted 2009-04-07

OK, so I wanted to use my Aspire One to do presentations. However – getting dual screen to work was quite a lot of work.

I found a simple solution, which I am going to outline step-by-step for your convenience. This is all based on Fedora 10, 32bit, fully updated.

Result will be:

  • External VGA runs with 1024×768 @ 60 Hz, good enough for most projectors out there, with a single click
  • The display of the Aspire stays fully usable
  • The GNOME panels stay on the laptop

So step by step.

First – open a root shell because we will do some evil hacks.

We need to create an xorg.conf file, which normally doesn’t exist. so type

# Xorg -configure :1

Don’t be surprised. Your screen will flicker around. After a few seconds you will find a new file in your directory called xorg.conf.new. Copy tis file to the X11 directory:

# cp xorg.conf.new /etc/X11/xorg.conf

Now we need to make a few changes. First we need to switch down to 16 bit colors, due to the limited graphic memory of my Aspire One. Second we need to create a bigger virtual screen.

So find the section called

Section "Screen"<br /> Identifier "Screen0"<br /> Device     "Card0"<br /> Monitor    "Monitor0"

Right there add a line with

Default Depth 16

This forces X to use 16bit colors, making sure the extended display will fit in the 8 MB of graphic memory.

Now go down in xorg.conf and find the section

SubSection "Display"<br /> Viewport   0 0<br /> Depth     16<br /> EndSubSection

And add a line with

Virtual 2048 2048

so the whole section looks like this:

SubSection "Display"<br /> Viewport   0 0<br /> Depth     16<br /> Virtual 2048 2048<br /> EndSubSection

OK. Done with that part. Now the next part. We want to make sure that we can switch the layout in a very simple way. I am pragmatic. So no fancy GUI or stuff. What I need is to be able to present. So when I hook up a projector, I want to switch the VGA to a fixed 1024×768 resolution at 60 Hertz. This is compatible with most projectors. So I wrote a little shellscript that also makes sure that the top and bottom panels are at the right place – on my laptop.

I stored this under /usr/local/bin/vgaswitch:

#!/bin/sh<br /> /usr/bin/xrandr | grep "VGA connected"<br /> if [ $? = 0 ] ; then<br /> echo "VGA connected, setting VGA to 1024x768 @ 60 Hz"<br /> /usr/bin/xrandr --output LVDS --auto --output VGA --mode 1024x768 --rate 60 --right-of LVDS<br /> # Now move the panels back to the laptop screen<br /> gconftool-2 --set "/apps/panel/toplevels/bottom_panel/monitor" --type integer "1"<br /> gconftool-2 --set "/apps/panel/toplevels/top_panel/monitor" --type integer "1"<br /> else<br /> echo "No VGA connected, back to single screen"<br /> /usr/bin/xrandr --output LVDS --auto --output VGA --off<br /> # Now move the panels back to the laptop screen<br /> gconftool-2 --set "/apps/panel/toplevels/bottom_panel/monitor" --type integer "0"<br /> gconftool-2 --set "/apps/panel/toplevels/top_panel/monitor" --type integer "0"<br /> fi

Make the script executable with a chmod a+x /usr/local/bin/vgaswitch

The final step is to add a new panel launcher that calls the script. Done.

So now when I hook up a projector, I click on the icon that calls the script and – TADAAA! Remove the VGA cable, click it again, all back to normal. I am happy now 🙂

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