Configuring touchpad resolution with libinput

Question

I got a ThinkPad x240 and it has some known issues with jumpy touchpad behaviour in linux because of the difference in horinzontal and vertical resolution. The former solution (in xorg) was to put some config into /etc/X11/xorg.conf.d/ (see Here, Here). But now I am in Ubuntu 17.10 and therefor gnome with wayland. xinput list shows the following:

⎡ Virtual core pointer                      id=2    [master pointer  (3)]
⎜   ↳ Virtual core XTEST pointer                id=4    [slave  pointer  (2)]
⎜   ↳ xwayland-pointer:13                       id=6    [slave  pointer  (2)]
⎜   ↳ xwayland-relative-pointer:13              id=7    [slave  pointer  (2)]
⎣ Virtual core keyboard                     id=3    [master keyboard (2)]
    ↳ Virtual core XTEST keyboard               id=5    [slave  keyboard (3)]
    ↳ xwayland-keyboard:13                      id=8    [slave  keyboard (3)]

There are several files in /usr/share/X11/xorg.conf.d/: 10-amdgpu.conf 10-radeon.conf 50-synaptics.conf 10-quirks.conf 40-libinput.conf 70-wacom.conf

I tried adding the 50-synaptics.conf to match the one here except I changed the line MatchProduct to this MatchIsTouchpad "on". I also tried editing the 40-libinput.conf:

Section "InputClass"
    Identifier "libinput touchpad catchall" 
    MatchIsTouchpad "on"
    MatchDevicePath "/dev/input/event*"
    Option "VertResolution" "100"
    Option "HorizResolution" "65"
    Driver "libinput"
EndSection

None of this config files helped me solve my problem. Afaik the only 2 settings I need are VertResolution and HorizResolution. How can I set these for my touchpad and permanent?

Solution

With all the different X implementations, The most reliable method is to set input device options is by using xinput as shown In this answer. In your case the "option name" you want to look for will be something like "resolution" depending how your device names the options.

Comments

[Boris Hamanov]

At the login prompt, you can switch from wayland back to xorg, and maybe some of your previous work can work again. Wayland is not going to be the primary DE in 18.04, and may go away after that. It's just not up to the task yet.

[Pierre ALBARÈDE]

I have read elsewhere that the lexicographic file name order determines which driver is used, that's why file names begin with numbers, so if you want to use synaptics you should rename 50-synaptics.conf to 30-synaptics.conf. This might freeze the trackpad, take precautions.