[Bug 1897553] [NEW] Palm detect pressure is too easy to trigger so that the cursor stalled

[Launchpad Bug Tracker]

You have been subscribed to a public bug by Kai-Chuan Hsieh (kchsieh):

[Impact]

 * ALPS new i2c touchpads have capabilities for reporting ABS_PRESSURE and
   ABS_MT_PRESSURE event, However, it is very easy to over the default
   palm detect by pressure threshold 130. When the threshold is achieved,
   the cursor will be stalled, and not be able to keep following the
   finger's movement.

[Test Case]

 * For touchpad vid 0488, and have pressure capabilities.

   The pressure capability can be easily obtain by evtest tool, there 
   should be ABS_PRESSURE and ABS_MT_PRESSURE event in ABS event type.

   Test step:
   Install libinput-tools
   1. $ sudo apt install libinput-tools
   2. $ sudo libinput measure touchpad-pressure
   3. Generally move the finger, the pressure max should not exceed the
      palm pressure detect threshold

[Regression Potential]

 * It only impacts ALPS i2c models
 * It won't impact the touchpad without capability to report pressure event.
 * For those touchpad with pressure capability will make the palm detect 
   pressure be less sensitive. However, ALPS said its firmware can support 
   firmware labeling palm detection, so it is okay that the palm detect 
   pressure become less sensitive.

[Other Info]

 * The upstream commit has merged
   https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/505

** Affects: oem-priority
     Importance: Undecided
         Status: New

** Affects: libinput (Ubuntu)
     Importance: Undecided
     Assignee: Kai-Chuan Hsieh (kchsieh)
         Status: In Progress


** Tags: oem-priority originate-from-1891472 originate-from-1891979 somerville
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Palm detect pressure is too easy to trigger so that the cursor stalled
https://bugs.launchpad.net/bugs/1897553
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