When setting the acceleration to the minimum, it is set to 0, whereas the minimum value accepted by libinput is -1. Since 0 is the default value anyway, I cannot actually decrease the mouse acceleration speed. Reproducible: Always Steps to Reproduce: 1. Go to System settings > Input devices > Touchpad > Pointer Motion. 2. Set the acceleration to the minimum (maximum left). Actual Results: $ sudo xinput list-props "DLL0704:01 06CB:76AD Touchpad" |grep "274" libinput Accel Speed (274): 0.000000 Expected Results: $ sudo xinput list-props "DLL0704:01 06CB:76AD Touchpad" |grep "274" libinput Accel Speed (274): -1.000000 Using Arch Linux (up-to-date), Touchpad KCM 5.5.3, libinput 1.1.4, xf86-input-libinput 0.16.0, Xorg server 1.18.0.
Same problem to me. https://bbs.archlinux.org/viewtopic.php?pid=1686729 https://forum.kde.org/viewtopic.php?f=66&t=138655 libinput is the default library for pointing devices. Please fix this bug.
As you have discovered, Libinput support here is poor to nonexistent. Fixing that is tracked with https://bugs.kde.org/show_bug.cgi?id=383379 As a workaround, you can either remove Libinput or configure it via .conf files if you're using Xorg: https://wiki.archlinux.org/index.php/Libinput#Configuration *** This bug has been marked as a duplicate of bug 383379 ***
This was fixed for the Wayland version with https://cgit.kde.org/plasma-desktop.git/commit/?id=dd1244d6676620c06011b6c1db0c0ff3d5cdf0ab The Xorg version is in progress and should be released in 5.14 as well.