Public bug reported:
Hardware: Acer Swift SFX14-73G
Touchpad: PIXA4812:00 093A:4812 (I2C-HID)
OS: Kubuntu 24.04
Kernel: 6.17.0-14-generic
Session: X11 (KDE Plasma)
Symptoms:
- Touchpad detected by kernel and libinput
- Click works
- Finger contact detected in libinput debug-gui
- Cursor does not move, or moves with severe stuttering
- libinput reports repeated "kernel bug: Touch jump detected and discarded"
- Touch jump occurs on nearly every first contact frame
Steps already attempted:
1. Added /etc/libinput/local-overrides.quirks with AttrPressureRange=2:1
→ Cursor started moving but with heavy stuttering
2. Added /etc/X11/xorg.conf.d/41-ignore-pixa4812-mouse.conf
to ignore duplicate PIXA4812 Mouse and Stylus nodes
→ Reduced conflicts but stuttering persists
3. Tested AttrResolutionHint values (4x4, 8x8, 24x24) → no improvement
4. Tested EVDEV_ABS fuzz override (:::4 on axes 00,01,35,36) → no improvement
5. Tested AttrPressureRange values (5:3, 2:1) → 2:1 gives most movement
but touch jumps still cause regular tracking interruptions
Root cause identified:
The touchpad firmware sends position coordinates that jump by large amounts
on the first event of each new contact. libinput detects these as impossible
physical movements and discards them, causing tracking to reset and the cursor
to stutter or freeze for up to 1 second between movements.
libinput debug-events shows POINTER_MOTION events arriving in bursts
separated by 0.7-1.0 second gaps, each gap coinciding with a
"Touch jump detected and discarded" message.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Attachment added: "Commands typed to gather intel"
https://bugs.launchpad.net/bugs/2143915/+attachment/5951355/+files/bugreport.zip
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https://bugs.launchpad.net/bugs/2143915
Title:
PIXA4812:00 093A:4812 (Acer Swift SFX14-73G): repeated touch jump
causes severe cursor stuttering
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