[PATCH libinput 0/4] Lenovo X1 Carbon 3rd support

[Peter Hutterer]

Lenovo is back with a new generation hardware, the trackpoint's physical
buttons are back, and our headache is back too. Lenovo decided to wire the
buttons to the touchpad so they show up as BTN_0, 1, 2. Which means we have
to re-route them through the trackpoint device, much like we already do for
the T440 generation software buttons.

So we have one more special case for this hardware and need to treat it
separately. Turned out to be relatively easy, but we need udev to tag the
device for us - BTN_0 etc. are overloaded on other touchpads for scroll
buttons [1] so we can't just apply this on the general case.

Cheers,
  Peter

[1] which we don't support in libinput (yet, anyway).