T480s Trackpoint drifts

[Peter Hutterer]

On Wed, Mar 21, 2018 at 11:14:28AM +0800, Kai Hendry wrote:
> On Tue, 20 Mar 2018, at 12:05 PM, Peter Hutterer wrote:
> > what exactly is drift in this context? it moves on its own to the edge of
> > the screen?
> 
> It generally just moves diagonally south west for about a cm. Sometimes
> all the way to the bottom left. Initially I googled around and people said
> it was "re-calibrating"..

yeah, that's a built-in trackpoint feature that we don't have control over.
 
> > As for the drifting, is this something on your device only or a general
> > issue affecting this class of devices? Try playing around with the knobs 
> > in 
> > /sys/class/input/event18/device/device (replace event18 with your event 
> > node number)
> 
> Which knobs? Is there a guide?

judging by the output in the .txt file, you didn't run the cd command
correctly and ended up in some other device's directory. I'm honestly not
sure if there's a guide or even documentation but you can find bits and
pieces with google. drift_time is probably the key here, maybe resetafter or
resync_time. At some point I had a pdf somewhere that described some of
these but, ...

> > run libinput measure trackpoint-range and go from there, it's likely that
> > you need a custom range for that device. And the speed setting can be
> > changed, I'm having a hard time believing that at the lowest speed setting
> > it's still too fast given that it's almost tar-like at that speed on every
> > device I've tested.
> 
> https://www.youtube.com/watch?v=gDzWBhcOcCY
> https://s.natalian.org/2018-03-21/libinput.txt

> 
> > did you try changing the touchpad speed settings?
> 
> How do I do that? xinput?

use the gnome control center to change the pointer speed. or yeah, the
libinput Accel Speed property, set it to -1 and you'll have tar galore.

https://wayland.freedesktop.org/libinput/doc/latest/trackpoints.html matters
too

Cheers,
   Peter