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avila
Asked: 2018-04-29 00:27:24 +0800 CST

erratic behaviour of trackpoint on thinkpad t420s [UBUNTU 18.04]

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I just upgraded to Ubuntu 18.04 and the trackpoint shows an erratic behaviour. When moving the cursor in one direction, it first moves in some direction and then moves the right way.

It is a strange behaviour, as though there is some kind of momentum (inertia) "stuck" in the trackpoint that is released when I start moving again, after some time at rest.

The issue only happens with the trackpoint, and also only when both moves are dont with the trackpoint. (that is, if I move with the mouse (or touchpad), and then with the trackpoint, no problem.)

It was working fine with UBUNTU 17.10.

Here is the ouput of a relevant command.

avila@t420s ~> xinput list-props "TPPS/2 IBM TrackPoint"

Device 'TPPS/2 IBM TrackPoint':
Device Enabled (142):   1
Coordinate Transformation Matrix (144): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
libinput Natural Scrolling Enabled (281):   0
libinput Natural Scrolling Enabled Default (282):   0
libinput Scroll Methods Available (285):    0, 0, 1
libinput Scroll Method Enabled (286):   0, 0, 1
libinput Scroll Method Enabled Default (287):   0, 0, 1
libinput Button Scrolling Button (288): 2
libinput Button Scrolling Button Default (289): 2
libinput Middle Emulation Enabled (290):    0
libinput Middle Emulation Enabled Default (291):    0
libinput Accel Speed (292): -0.683453
libinput Accel Speed Default (293): 0.000000
libinput Accel Profiles Available (294):    1, 1
libinput Accel Profile Enabled (295):   1, 0
libinput Accel Profile Enabled Default (296):   1, 0
libinput Left Handed Enabled (297): 0
libinput Left Handed Enabled Default (298): 0
libinput Send Events Modes Available (266): 1, 0
libinput Send Events Mode Enabled (267):    0, 0
libinput Send Events Mode Enabled Default (268):    0, 0
Device Node (269):  "/dev/input/event8"
Device Product ID (270):    2, 10
libinput Drag Lock Buttons (283):   <no items>
libinput Horizontal Scroll Enabled (284):   1
thinkpad trackpoint libinput 18.04

1 Answers

  1. Best Answer

    Disabling the acceleration profile helps:

    xinput --set-prop 'TPPS/2 IBM TrackPoint' 'libinput Accel Profile Enabled' 0, 1

    Then you might want to increase your pointer's speed:

    xinput --set-prop 'TPPS/2 IBM TrackPoint' 'libinput Accel Speed' 1

    Since the next startup the acceleration profile will be enabled again by default you can create a script that includes the above commands and is run automatically after restart.

    Hope that helps.

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