How to adjust touchpad pressure in Libinput puppies

Marv · Post by **Marv** » Sun Jan 09, 2022 2:05 am

This applies to all the recent Slackware derivatives, not fossapup64, don't know what else does use libinput but running xinput list and then xinput list-props <ID> with the touchpad ID from the xinput list output will tell what driver is used. Libinput now does a barely acceptable job handling my Synaptics brand touchpads but still stinks on the Alps one in my Fujitsu S762. Evdev etc. in fossapup64 does ok. Synaptics did best.

Setting the finger pressure helps a great deal but it can not be done in the usual /etc/X11/xorg.conf.d/xx-libinput.conf files. It can be done in the following manner:

Create an empty file, /etc/libinput/local-overrides.quirks, and paste the following into it (use your touchpad name from the xinput list):

Code: Select all

[Touchpad pressure override]
MatchUdevType=touchpad
MatchName=*AlpsPS/2 ALPS DualPoint TouchPad
AttrPressureRange=92:90

and save it. Default ownership root:root and permissions Anyone,Only Owner, Nobody are OK. No spaces(tested) or tabs(?) at line beginnings.

In the AttrPressureRange entry, the first number is the pressure for a touch, the second is the number for release after a touch. In my case, both increasing the pressures and reducing the hysteresis helped tame the ALPS jitterbugging, present both in adaptive and flat acceleration profiles.

Play with the numbers, an X restart is needed for Libinput to pick up the quirks. I use twofinger scrolling. These numbers are too high for good edge scrolling in my lappies and in Libevent it looks like the 'scroll press pressure' can't be set separately -like too much else- I am also using this with my Synaptics brand touchpads now, an example from there is:

Code: Select all

[Touchpad pressure override]
MatchUdevType=touchpad
MatchName=*SynPS/2 Synaptics TouchPad
AttrPressureRange=85:80

A small thing, not perfect, but I was ready to use the otherwise perfect S762 as a discus. Even looked at a touchpad swap from a parts S761 first but they had changed too much between the years so that was a fail.

The link I found most useful is here:https://wayland.freedesktop.org/libinpu ... uirks.html

Edited once: grammar and link