Ubuntu
xserver-xorg-input-synaptics package

  1. Bug #1287148
  2. Comment #0

Comment 0 for bug 1287148

Revision history for this message
Larry Hastings (larry-hastings) wrote : Thinkpad clickpad + Trackpoint cannot emulate middle button scrolling

I'm testing with a freshly-updated Trusty Tahir daily (2014/March/2) on a Lenovo X1 Carbon (2014 refresh) laptop.

IBM/Lenovo Thinkpad laptops have a "Trackpoint": a red "joystick mouse" in the middle of the keyboard. Historically this is accompanied by three mouse buttons directly below the space bar. One beloved feature: if you hold down the middle mouse button, you can scroll a window up/down/left/right with the Trackpoint. This feature is implemented in X with the "Evdev Wheel Emulation" properties of the xinput driver for the Trackpoint device.

The latest Thinkpad laptops (X240, X1 Carbon 2014 refresh) remove the hard buttons, and have a "clickpad" instead of a trackpad. One must use the "soft" mouse buttons provided by the clickpad. But now we have a problem. The clickpad soft buttons are implemented in the Synaptic driver. And the Synaptic driver doesn't support middle-button-scrolling.

If I run
  % xinput --list-props "TPPS/2 IBM TrackPoint"
I see property entries starting with "Evdev Wheel Emulation". Setting them on this device doesn't enable middle-button-scrolling.

And if I run
  % xinput --list-props "SynPS/2 Synaptics TouchPad"
I don't see those property entries at all. I tried setting them manually with "xinput --set-int-prop" but they were ignored.

One of the maintainers of Arch Linux got middle-button-scrolling with a Trackpoint + clickpad to work! But he had to create a new driver. It looks like he started with the evdev driver, and merged in support for the Synaptics and Trackpoint devices. The resulting driver is published here:

https://bitbucket.org/esrevinu/xf86-input-evdev-trackpoint

It would be fantastic if Ubuntu 14.04 also supported this feature. Thanks!