Bug 90528

Summary: Add thumb detection
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:
Bug Depends on:    
Bug Blocks: 90261, 90526, 90527    

Description Peter Hutterer 2015-05-20 06:17:14 UTC 
For a thumb press on the T440s I get an ABS_MT_PRESSURE minimum of 100 to 110 (range [0, 255]), with the first one or sometimes two events being in the 80-100 range. Finger data is in the 60-90 range.

On an X220t, the thumb pressure is all over the place. This touchpad is quite small, so the only way to use a thumb here is to only partially touch the touchpad, so most thumb presses are actually in the 30-60 range.
Finger data is in the 50-90 range.

Based on those two touchpads: what may work is having a zone on the touchpad, similar to touchpad buttons to label a thumb (or at least increase confidence that it is a thumb).

We may need to limit thumb detection to certain touchpads over a specific size.
Comment 1 Benjamin Tissoires 2015-05-21 19:22:33 UTC 
On an Elan touchpad (10x7 cm): regular finger 25-50, thumb 75-100.
On an Atmel touchpad (10x7 cm): regular finger -> initial reported value ~30 then roughly 60-80, for the thumb -> intial reported value of 70-90, then roughly 110-130.

Good luck with that :)
Comment 2 Peter Hutterer 2015-07-09 02:46:44 UTC 
commit 3dcf28b919ae598506852b408829a6627168e803
Author: Peter Hutterer <peter.hutterer@who-t.net>
Date:   Wed May 27 18:25:49 2015 +1000

    touchpad: add pressure-based thumb-detection


commit 4a463ca70228eaf0d3b676b6d7392b3cd5eb8f00
Author: Peter Hutterer <peter.hutterer@who-t.net>
Date:   Mon Jul 6 15:22:45 2015 +1000

    touchpad: work thumb detection into the tap state machine

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