Running "sudo udevadm trigger -s input" results in touchpad configuration being reset

[jroovy]

systemd version the issue has been seen with

Systemd 243.162

Used distribution

Arch Linux, KDE Plasma 5.17.3
Kernel 5.3.11-arch1-1, x86_64

Expected behaviour you didn't see

…

Unexpected behaviour you saw

Touchpad behavior in Plasma Desktop is reset to defaults

What caused this issue

Using KDE's Partitionmanager to modify partitions caused this issue since the debug info provided here: https://bugs.kde.org/show_bug.cgi?id=413973 shows that Partitionmanager runs udevadm trigger as root which in turn caused this touchpad issue

Steps to reproduce the problem

1. Open KDE Plasma's touchpad configuration dialog
2. Enable tap-to-click and inverse scrolling and apply changes
3. Run "sudo udevadm trigger -s input"
4. Touchpad behavior is reset back to defaults (tap-to-click disabled, scrolling uninversed)

System specs

Lenovo Ideapad 320 (2016)
Intel i5-7200U
Elan touchpad (based on the vendor-provided Windows touchpad drivers)

[poettering]

well, it's probably libinput or KDE which resets the settings on a "change" uevent. @whot any idea?

I doubt this is an upstream systemd issue though, and we should probably close that here hence.

[poettering]

(that partitionmanager really shouldn't trigger the whole system though. That's just a bad idea, and not necessary)

[whot]

libinput doesn't do anything with the "change" signal, we only handle add/remove. So this must be somewhere within KDE.

[poettering]

Anyway, let's close this here. Please report to KDE.