SUMMARY 5.26.90 (5.27 beta) has added libinput 1.19 smooth/high-resolution scrolling to the Plasma Wayland session. This is a welcome addition, however it cannot be configured, and it is an issue: 1: Users may dislike this feature. 2: in games (e.g. Minecraft, scrolling through items in the hotbar becomes unreliable due to scroll interpolation or Counter Strike: Global Offensive, where the same applies to the weapon selector) There should be an option to easily disable this feature within kcm_mouse. libinput allows for configuring this feature, so it should be possible. STEPS TO REPRODUCE 1. Start a Plasma Wayland session. 2. Open System Settings 3. Navigate to Input Devices > Mouse 4. Observe options 5. Navigate to Workspace Behavior > General Behavior 6. Observe options OBSERVED RESULT There is no option to disable smooth/high resolution scrolling, per mouse or system-wide. EXPECTED RESULT There should ideally be an option to disable smooth/high resolution scrolling, both per mouse and system-wide. SOFTWARE/OS VERSIONS Linux: Arch Linux vanilla kernel 6.1.9-arch1-1 KDE Plasma Version: 5.26.90 KDE Frameworks Version: 5.102.0 Qt Version: 5.15.8 ADDITIONAL INFORMATION KDE Plasma Wayland session.
Also affects the X11 session on Neon. This smooth scrolling change broke the following things for me: - Scrolling over the volume slider in Elisa. - Scrolling over the volume applet on the system tray. - Scrolling over comboboxes started skipping over several items. I had to add the following libinput local override to make scrolling usable again: [Logitech M705 Marathon Mouse] MatchVendor=0x046D MatchName=Logitech M705 AttrEventCodeDisable=REL_WHEEL_HI_RES;
Some more details about how this broke my volume controls because I realized it might not be obvious: With these high resolution scrolling changes one or two ratchet clicks of wheel rotation started going from 0% straight to 100% of volume. Previously with low-res scrolling this took 20 ratchet clicks. It also introduced constant scroll twitching that was suppressed before by low resolution scrolling.
It appears the weird behavior of high resolution scrolling in games is a due to Bug 464776, which has been fixed in a commit (https://invent.kde.org/plasma/kwin/-/commit/9f494da9fa29fd2a8abd34e5bde95d531026301e) right after the beta was tagged.
Actually, if I understand correctly, the fixed bug would also affect other clients that expect low resolution scrolling, like the volume sliders you mentioned.
I think everything described here (scrolling in games, the volume control) is due to that fixed bug. *** This bug has been marked as a duplicate of bug 464776 ***
I had a feeling too, but couldn't find it. Thanks, John!