kern/56476: Pointer jumps with synaptics driver

[mlelstv%serpens.de@localhost]

>Number:         56476
>Category:       kern
>Synopsis:       Pointer jumps with synaptics driver
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Oct 30 14:10:00 +0000 2021
>Originator:     Michael van Elst
>Release:        NetBSD 9.99.92
>Organization:
	
>Environment:
	
	
System: NetBSD tazz 9.99.92 NetBSD 9.99.92 (GENERIC) #4: Sat Oct 30 13:58:25 UTC 2021 mlelstv@slowpoke:/scratch2/obj.amd64/scratch/netbsd-current/src/sys/arch/amd64/compile/GENERIC amd64
Architecture: x86_64
Machine: amd64
>Description:
Since the update of synaptics.c to 1.73 the contact to the touch pad
jumps the pointer to a position resembling the absolute position on the
touch pad.

>How-To-Repeat:
Put finger to the left top quadrant of the touchpad and see the pointer
jump a few centimeters to the top left. Put finger on the right top
and see it jump to the right. You can touch any position and the pointer
roughly follows as if the touchpad would use absolute coordinates.

Moving the pointer outside that rectangle is only possible thanks to
pointer acceleration.
>Fix:
Reverting to 1.72 restores the normal behaviour.

>Unformatted: