thinkpad-acpi: handle HKEY 0x4010, 0x4011 events

thinkpad-acpi: handle HKEY 0x4010, 0x4011 events

Handle events 0x4010 and 0x4011 so that we do not pester users about them.

These events report when the thinkpad is docked/undocked to a native
hotplug dock (i.e. one that does not need ACPI handling, nor is represented
in the ACPI device tree).  Such docks are based on USB 2.0/3.0, and also
work as port replicators.

We really want a proper dock class to report these, or at least new input
EV_SW events.  Since it is not clear which one to use yet, keep reporting
them as vendor-specific ThinkPad events.

WARNING: As defined by the thinkpad-acpi sysfs ABI rules of engagement, the
vendor-specific events will be REMOVED as soon as generic events are made
available (duplicate events are a big problem), with an appropriate update
to the thinkpad-acpi sysfs/event ABI versioning.  Userspace is already
prepared to provide easy backwards compatibility for such changes when
convenient to the distro (see acpi-fakekey).

* Event 0x4010: docking to hotplug dock/port replicator
* Event 0x4011: undocking from hotplug dock/port replicator

Typical usecase would be to trigger display reconfiguration.

Reports mention T410, T510, and series 3 docks/port replicators.  Special
thanks to Robert de Rooy for his extensive report and analysis of the
situation.

http://www.thinkwiki.org/wiki/ThinkPad_Port_Replicator_Series_3
http://www.thinkwiki.org/wiki/ThinkPad_Mini_Dock_Series_3
http://www.thinkwiki.org/wiki/ThinkPad_Mini_Dock_Plus_Series_3
http://www.thinkwiki.org/wiki/ThinkPad_Mini_Dock_Plus_Series_3_for_Mobile_Workstations
http://lenovoblogs.com/insidethebox/?p=290

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Reported-by: Claudius Hubig <claudiushubig@chubig.net>
Reported-by: Doctor Bill <docbill@gmail.com>
Reported-by: Korte Noack <gbk.noack@gmx.de>
Reported-by: Robert de Rooy <robert.de.rooy@gmail.com>
Reported-by: Sebastian Will <swill@csail.mit.edu>