dock-undock script for w520 with the mini dock plus. To install, place in /etc/init.d/. and run 'update-rc.d dock-undock.sh defaults'.

dock-undock.sh

#!/bin/sh

### BEGIN INIT INFO
# Provides:          dock-undock.sh
# Required-Start:    $local_fs $remote_fs $bumblebeed
# Required-Stop:   
# Default-Start:     2 3 4 5
# Default-Stop:
# Short-Description: Check if laptop is docked or undocked and change XOrg.
# Description: Check if laptop is docked or undocked and change XOrg config.
### END INIT INFO

set -e

DOCKED=`hwinfo | grep "ThinkPad Mini Dock Plus Series 3" | wc -l`
LOG=/var/log/docked_status.log

if [ $DOCKED -gt 0 ]; then
   cp /etc/X11/xorg.conf.docked /etc/X11/xorg.conf
   YN="{DOCKED}"
   echo ON | tee /proc/acpi/bbswitch
else
   cp /etc/X11/xorg.conf.undocked /etc/X11/xorg.conf 
   YN="{UNDOCKED}"
   echo OFF | tee /proc/acpi/bbswitch
fi

echo "[`date`] DOCK STATUS = $YN" >> $LOG

exit 0