Cursor "trembles" when holding finger still

[WhyNotHugo]

[Sorry, I'd initially hit enter by accident when typing the title and posted an empty issue]

The cursor "trembles" when I hold my finger still on the touchpad. I'm using a 2017 MacBook Pro. The effect is also visible (but harder to demostrate) when moving the mouse around.

$ xinput --list-props 12
Device 'Apple SPI Touchpad':
        Device Enabled (136):   1
        Coordinate Transformation Matrix (138): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
        Trackpad Disable Input (277):   0
        Trackpad Sensitivity (278):     1.000000
        Trackpad Touch Pressure (279):  5, 5
        Trackpad Button Settings (280): 1, 1
        Trackpad Button Emulation Settings (281):       0, 1, 100
        Trackpad Button Emulation Values (282): 1, 3, 2
        Trackpad Tap Settings (283):    50, 120, 400
        Trackpad Tap Button Emulation (284):    0, 3, 2, 0
        Trackpad Thumb Detection (285): 1, 0
        Trackpad Thumb Size (286):      25, 70
        Trackpad Palm Detection (287):  1, 0
        Trackpad Palm Size (288):       40
        Trackpad Gesture Settings (289):        10, 100
        Trackpad Smooth Scroll (290):   1
        Trackpad Scroll Settings (291): 150, 20, 0
        Trackpad Scroll Buttons (292):  5, 4, 7, 6
        Trackpad Swipe Settings (293):  300, 300, 0
        Trackpad Swipe Buttons (294):   16, 18, 19, 17
        Trackpad Swipe4 Settings (295): 700, 300, 0
        Trackpad Swipe4 Buttons (296):  20, 0, 0, 0
        Trackpad Scroll Coasting (297): 0.100000, 200.000000
        Trackpad Edge Scroll Settings (298):    105, 20, 0, 4, 5, 6, 7
        Trackpad Edge Sizes (299):      0, 10, 0, 0
        Trackpad Scale Distance (300):  150
        Trackpad Scale Buttons (301):   12, 13
        Trackpad Rotate Distance (302): 150
        Trackpad Rotate Buttons (303):  14, 15
        Trackpad Hold1Move1 Stationary Settings (304):  20, 1
        Trackpad Hold1Move1 Settings (305):     1, 0, 1000
        Trackpad Hold1Move1 Buttons (306):      1, 1, 1, 1
        Trackpad Drag Settings (307):   1, 350, 40, 200, 500
        Trackpad Axis Inversion (308):  0, 0

[I'm trying to attach a recording, but working on getting something sane].

[WhyNotHugo]

Example: https://imgur.com/a/np1Z2

Sometimes it trembles more, sometimes less.

[p2rkw]

Build this https://github.com/p2rkw/xf86-input-mtrack/tree/filter_fuzz and fine tune SN_COORD: https://github.com/p2rkw/xf86-input-mtrack/blob/filter_fuzz/src/capabilities.c#L29

[WhyNotHugo]

Sorry for the delay replying. I was out for a couple of week and couldn't get around to trying this before.

I tried that branch and the issue seems to be gone. I don't see any side effects either, so didn't need to fine-tune the value you mentioned any further.

[p2rkw]

There's still problem with fuzzing, because with this path I can't draw straight, long line at 45 degrees: line have step-like patterns. Please check it out in some drawing application.

[WhyNotHugo]

It looks pretty much okay to me (there's an obvious lack of anti-aliasing, but it kinda looks as expected):

Also, sorry, I don't have a good pulse.

[p2rkw]

Your lines are wave'y just like mine.

Probably all 3 SN_* values should be increased.

[fbarriga]

work ok for me