Bug 197885

Hello,

This is the description of a bug that was probably introduced with kernel 4.11 (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d5dee39b27201f9f5460eca55efcc91a663b738c)
I could successfully reproduce a behaviour of a "jumping pointer" in kernel 4.11 on 3 different devices with this touchpad, but not in kernel 4.10.

A second issue, missing capabilities of the touchpad (probably not advertised correctly), is consistent up to the latest kernel.


The pointer jumps occur regularly when moving; it seems to leap forward quite some pixels in the direction of movement.
The distance of the jump seems to be dependend on the movement speed of the pointer; the faster I move it, the further the jump.
This can occur in all directions.


The mentioned second issue has a workaround due to some unrelated option that forces libinput to enable options for the touchpad that were not advertised.
The touchpad is a 1-button clickpad that supports gestures.
The issue is the missing "clickfinger" option (the name in libinput): 2-finger-tap works, 2-finger-click does not, although it should. Option buttonareas is available, but there is no middle or right button area.


The jumping pointer issue makes the touchpad almost unusable.
I am more than happy to provide any more input or help.



Thanks for the good work!