Created attachment 118188 [details] Libinput recording that demonstrates issue, showing slow scrolling SUMMARY When using touchpad input with the two finger scroll gesture, STEPS TO REPRODUCE 1. Open any app that supports high resolution scrolling with Libinput (dolphin, firefox with wayland patch, plasma settings) 2. Use 2 finger scroll gesture very slowly across touchpad (less than 5mm/sec) OBSERVED RESULT No scroll event occurs EXPECTED RESULT Scrolling continues, but is slower than normal SOFTWARE/OS VERSIONS Linux/KDE Plasma: kernel 4.20.10-arch1-1-ARCH (available in About System) KDE Plasma Version: 5.15.0 KDE Frameworks Version: 5.55.0 Qt Version: 5.12.1 Libinput: 1.12.6 ADDITIONAL INFORMATION Not reproduceable on Plasma on Xorg, and does not occur on Gnome Xorg or Gnome Wayland. This is limited to exclusively Plasma on Wayland. Encountered on a Dell XPS 9560. No other system available to test.
This happens because KWin floors deltas. The fix for bug 404152 should address this issue.
Hm, so KWin _does_ process input before sending it to applications?
Yes, normal applications don't have access to input devices.
Is this resolved by https://phabricator.kde.org/D19000 or is there more related work required? As a side note, does the patch in that differential allow kinetic scrolling to work as well? I seem to remember kinetic scrolling (in e.g. GTK apps) requiring axis source and axis stop information, but do not know if there is more to it than exposing what that patch does.
Kinetic scrolling in GTK apps already works fine for me, it's just Qt apps which seem to need that special something to make it work.
(In reply to Nate Graham from comment #5) > Kinetic scrolling in GTK apps already works fine for me, it's just Qt apps > which seem to need that special something to make it work. Just to clarify, is this as of 5.16 or is this using kwin with the mentioned diff applied?
For me, kinetic scrolling in GTK apps (well, GNOME apps that use an unmodified GTK ScrollView at least) has worked for ages and ages. It definitely did not require that patch.
(In reply to Sawyer Bergeron from comment #4) > Is this resolved by https://phabricator.kde.org/D19000 or is there more > related work required? It should be. Please reopen this bug report if there are still issues with scrolling in 5.17.