Bug 101435

Summary: use BTN_TOOL_TRIPLETAP for three-finger touch detection on 2-slot touchpads
Product: Wayland Reporter: Peter Hutterer <peter.hutterer>
Component: libinputAssignee: Wayland bug list <wayland-bugs>
Status: RESOLVED FIXED QA Contact:
Severity: normal    
Priority: medium CC: peter.hutterer
Version: unspecified   
Hardware: Other   
OS: All   
Whiteboard:
i915 platform: i915 features:

Description Peter Hutterer 2017-06-15 04:12:14 UTC 
From: https://bugzilla.redhat.com/show_bug.cgi?id=1455443

Summary: synaptics 2-slot touchpads give us pointer jumps when the third finger is down. The data we get is garbage, sometimes the two touches swap slots, sometimes we get two x/y positions within the same frame for the same slot, etc.
As a result, three-finger taps are unreliable.

This wasn't the case with synaptics because it merely relied on BTN_TOOL_TRIPLETAP and didn't use the same motion detection we have in libinput.
Comment 2 Peter Hutterer 2017-06-26 09:26:04 UTC 
commit be7da7f7daa3b551bb9418b62bc5490ddcfa21e7
Author: Peter Hutterer <peter.hutterer@who-t.net>
Date:   Thu Jun 15 14:13:26 2017 +1000

    touchpad: ignore the tap motion threshold if fingers > slots

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