Docking Solutions

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Docks allow users to connect a variety of external peripherals simply by attaching their ThinkPad to the dock.

Linux support

With recent distributions, docking and undocking should function out of the box. You can monitor this by running # udevadm monitor and when you dock or press the undock button you should see a flurry of events.

There are some issues though

No event on undock

There are various possible reasons for not getting ACPI docking or undocking events;

  1. port-replicators have never supported ACPI docking events
  2. newer docks (series 3 and newer from 2009 onwards), instead of generating ACPI dock events, generate key events which are only supported by the thinkpad-acpi driver since kernel 3.0. And no default action is taken on receiving these events.
  3. prior to kernel 2.6.34 the ACPI Dock driver only registered the first logical Dock port, and subsequent dock ports where ignored. This effected the ThinkPad X40 with ThinkPad X4 Dock. For older kernels patches are available.

Filesystem corruption

Pressing the undock button will immediately unplug all dock attached devices. This can easily lead to problems, for instance if you have a USB or Ultrabay storage device attached to the dock and have a filesystem mounted RW, this can easily lead to filesystem corruption.

The solution for now is to always make sure any storage devices attached to the dock are unmounted BEFORE pressing the undock button.

External display issues

NOTE!
This only works for devices that register themselves as a dock through ACPI, it does not work for port replicators which are hidden to the OS.
NOTE!
Newer series 3 docks no longer register themselves as a dock, but instead behave like a port replicator, as such the below method does not work. They do however cause a key event on dock and undock which could be used as a trigger, but for now these key events are not exposed by the thinkpad-acpi driver before kernel 3.0

Docking or undocking will also not change the display configuration, which can lead to issues when your undock and your screensaver decided to put the unlock dialog on the secondary display, effectively requiring you to unlock the screensaver blind, before you can press Fn-F7 to restore your display setup to ThinkPad (LVDS) only. This last issue can be resolved by creating a custom udev rule and script as shown below. This script can also be used to take other actions on dock/undock such as automatically configuring your external display on dock.

create a file /etc/udev/rules.d/81-thinkpad-dock.rules 

KERNEL=="dock.0", ACTION=="change", RUN+="/usr/local/sbin/thinkpad-dock.sh"

Then create the file /usr/local/sbin/thinkpad-dock.sh 

#!/bin/sh
# wait for the dock state to change
sleep 0.5
DOCKED=$(cat /sys/devices/platform/dock.0/docked)
case "$DOCKED" in
	"0")
       #undocked event - lets remove all connected outputs apart from LVDS
       for output in $(/usr/bin/xrandr -d :0.0 --verbose|grep " connected"|grep -v LVDS|awk '{print $1}')
         do
         /usr/bin/xrandr -d :0.0 --output $output --off
       done
	;;
	"1")
	#docked event - sample will created extended desktop with DVI1 to the right of LVDS1
	#/usr/bin/xrandr -d :0.0 --output DVI1 --right-of LVDS1 --auto
	;;
esac
exit 0

And set it executable 

chmod +x /usr/local/sbin/thinkpad-dock.sh
NOTE!
The output names shown above are specific to the Intel video drivers. For the ATI Radeon driver they are different. But you best check your output names by running xrandr manually, and adjusting the script appropriately for your needs. The undock event should work on any ThinkPad where the graphics driver supports RandR and the ThinkPad LCD has LVDS in the name.

Part of this is based on information from a thread on the Ubuntu forums

Newer series 3 docks

There is a solution for the Series 3 docks: http://phihag.de/2012/thinkpad-docking.html

Available Docking Stations and Port Replicators

Withdrawn Docking Stations and Port Replicators

Monitor and Notebook Stands

Other

External Sources

FOOTNOTES [Δ]
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