fixing the trackpoint on ubuntu

Update: I can't believe it is the year 2020, I install 20.04, and again I am having the jumpy trackpoint on my x220. From what I read others have it with newer laptops as well. After a bit of digging around I got the impression that one needs to switch back from libinput first: ( see https://askubuntu.com/questions/1188069/on-18-04-lts-how-can-the-trackpoint-driver-be-changed-from-libinput-back-to-syn):

apt install xserver-xorg-input-synaptics-hwe-18.04 xserver-xorg-input-evdev-hwe-18.04
apt remove xserver-xorg-input-libinput xserver-xorg-input-libinput-hwe-18.04

After that install the file that is explained below. Now at least we have a non-jumpy pointer. Last step is to accelerate it a bit:

xinput set-prop "TPPS/2 IBM TrackPoint" 297 3

This can be written into a ~/.xinitrc file.

From what I understand the problem with the trackpoint is known, but is not going to be fixed in libinput - http://who-t.blogspot.com/2018/05/x-server-pointer-acceleration-analysis-part1.html

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Original part:

Combining advice from

https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-input-synaptics/+bug/1042069

and

http://www.x.org/wiki/Development/Documentation/PointerAcceleration/

had me create the following file in /usr/share/X11/xorg.conf.d/50-thinkpad-touchpad.conf:

Section "InputClass"
        Identifier "touchpad"
        MatchProduct "TPPS/2 IBM TrackPoint|DualPoint Stick|Synaptics Inc. Composite TouchPad / TrackPoint|ThinkPad USB Keyboard with TrackPoint|USB Trackpoint pointing device|Composite TouchPad / TrackPoint"
        Option "MinSpeed" "1"
        Option "MaxSpeed" "1"
        # tweak the X-server pointer acceleration
        Option "AccelerationProfile" "2"
        Option "AdaptiveDeceleration" "1000"
        Option "ConstantDeceleration" "16"
        Option "VelocityScale" "30"
        Option "AccelerationNumerator" "30"
        Option "AccelerationDenominator" "10"
        Option "AccelerationThreshold" "10"
EndSection

Section "InputClass"
        Identifier "touchpad"
        MatchProduct "Synaptics Inc. Composite TouchPad / TrackPoint (Stick)"
        Driver "evdev"
        Option "AccelerationProfile" "6"
        Option "ConstantDeceleration" "12"
        Option "VelocityScale" "30"
EndSection