Comment # 20 on bug 1120405 from Takashi Iwai

Thanks for the test.  It implies that this is no regression at least ;)

Meanwhile I found the missing piece.  Actually it's not one but more pieces.

First off, other distros seem to have inputattach program that supports Wacom
w8001 mode.  This is included in linuxconsole (on openSUSE, it's
linuxconsoletools package).

But our package removes inputattach program because the same named binary is
provided by gpm -- and it's a much older one that doesn't contain Wacom
support.

Then, the inputattach program should have been called by a systemd
wacom-inputattach@.service.  This is already found in the existing
65-wacom.rules udev rules.  However, our package misses this unit file, hence
nothing happens.
(I'm not sure whether xf86-input-wacom or libwacom should provide it, though.)

With those, the wacom_w8001 gets bound via serio on the given tty, and it
provides a proper input device...  I suppose.

Some information found at:
 
http://who-t.blogspot.com/2013/12/wacom-serial-devices-and-inputattach-in.html

And my previous udev rules must be superfluous once when this works.