Fun with xorg.conf

So I've finally got my ALPS / Synaptics touchpad working along with a compose key on debian (the ALPS touchpad comes with, among many other laptops, the Dell Inspiron 500m which I own).

The touchpad

For the touchpad, I need to thank this walkthrough along with this forum thread.

Before anything will work, you need to make sure that the evdev module is being compiled in your kernel (it wasn't) and is being loaded (that bit worked for free for me, but one comment on the above forum post suggested you needed to add it to /etc/modules). You can find the option under Device Drivers/Input Device Support/Event Interface in the kernel config (e.g. make menuconfig)


Now you need to edit your xorg.conf (found in /etc/X11). There are three things that you need to do:

• Load the synaptics module


• Add a new input device to ServerLayout


• Declare the input device

In order to load the synaptics module, add a line saying:

Load "synaptics"

to the "Module" section. Mine now looks like:

Section "Module"
        Load  "glx"
        Load  "extmod"
        Load  "xtrap"
        Load  "record"
        Load  "GLcore"
        Load  "dbe"
        Load  "dri"
        Load  "type1"
        Load  "synaptics"
EndSection

Now adding a new input device to ServerLayout is simple - just choose a name (I called it "ALPS") and add the line

InputDevice "your name for it here"

to the ServerLayout section just below the line saying

InputDevice "Configured Mouse"


Finally, add the declaration for the input device. A version with no clever options set is:

Section "InputDevice"
        Identifier "ALPS"
        Driver "synaptics"
        Option "SendCoreEvents" "true"
        Option "Device" "/dev/input/mouse1"
        Option "Protocol" "evdev"
        Option "SHMConfig" "on"
EndSection

(note that the identifier has to agree with the name you chose earlier). For a much more thorough list of settings you might wish to see the third page of the debuntu article here.

Assuming you got everything right, you should now be able to restart your X server and get exciting touchpad support. Note that to restart the X server, the best practice is to exit (gracefully) any open programs, log out of whatever desktop environment you're using and when you get to the display manager (xdm,kdm,gdm or whatever) hit Ctrl-Alt-Backspace.

The Compose Key

This is really simple, but it makes life much easier when writing auf Deutsch on an english keyboard. In your InputDevice section corresponding to your keyboard, add the line:
Option "XkbOptions" "lv3:ralt_switch, compose:ralt"
The relevant section in my xorg.conf now looks like this:

Section "InputDevice"
        Identifier  "Keyboard0"
        Driver      "kbd"
        Option      "XkbModel"      "pc105"
        Option      "XkbLayout"     "gb"
        Option      "XkbOptions"    "lv3:ralt_switch, compose:ralt"
EndSection

Once you've restarted the X server, Alt-Gr S, S should give ß and you can have the fun of discovering umlauts, graves, circumflexes etc. yourself. It's a bit like a more logical version of the system they used in Microsoft Word.