Comment 85 for bug 1746740

It's a so-called schmitt trigger, pressure needs to go above "down" to be detected as touch and below "up" to be released again. down > up to make the touch more resilient.

libinput:name:*CyPS/2 Cypress Trackpad:dmi:*svnDell:*pnXPSL322X*
 LIBINPUT_ATTR_PRESSURE_RANGE=105:60
 LIBINPUT_ATTR_PALM_PRESSURE_THRESHOLD=230

Something like this should work. Check /sys/class/dmi/id/modalias and adjust the dmi bit accordingly, make sure the svn and pn bits match. https://wayland.freedesktop.org/libinput/doc/latest/faq.html#faq_hwdb_changes

I'll need you to figure out that hwdb match though, I can't test this locally without the same machine so anything I'd merge is prone to be buggy.