Re: [PATCH 1/2] HID: multitouch: report MT_TOOL_PALM for non-confident touches

[Henrik Rydberg]

> > However, I interpret a firmware that send (confidence 1, tip switch 1)
> > and then (confidence 0, tip switch 0) a simple release, and the
> > confidence bit should not be relayed.
> This unfortunately leads to false clicks: you start with finger, so
> confidence is 1, then you transition the same touch to palm (use your
> thumb and "roll" your hand until heel of it comes into contact with the
> screen). The firmware reports "no-confidence" and "release" in the same
> report and userspace seeing release does not pay attention to confidence
> (i.e. it does exactly "simple release" logic) and this results in UI
> interpreting this as a click. With splitting no-confidence
> (MT_TOOL_PALM) and release event into separate frames we help userspace
> to recognize that the contact should be discarded.
This is in part why I objected to this patch on August 11th, 2017. 
Logically, the confidence state is a property of a contact, not a new 
type of contact. Trying to use it in any other way is bound to lead to 
confusion.

Henrik