So I just got a thinkpad e570. Even though the middle trackpoint button was recognized and working out of the box in windows as scroll it can't even be seen in any linux distro.
xev returns no output when it's pressed and "xinput list props 16" returns "unable to find device 16".
Is this fixable?
The bugfix for this was merged into Linux kernel 4.13rc6. So it should be available in two to three weeks.
So far installing xserver-xorg-input-libinput-hwe-16.04 (on Ubuntu 16.04.2) and reloading psmouse with proto=imps seems to enable the middle mouse button. But this disables two finger-scroll on the touchpad.
The issue is also discussed here: Touchpad while holding on touchpad it doesn't work
And a bug for Ubuntu was filed: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-libinput-hwe-16.04/+bug/1670492
The proper solution includes patching the psmouse kernel module. The kernel module fails to retrieve the extended button data. Forcing the right value fixes this. See: https://bugs.freedesktop.org/show_bug.cgi?id=100694
