libinput 1.7.0, intermittently erratic touchpad

[Peter Hutterer]

On Tue, Apr 04, 2017 at 05:01:53PM -0600, Chris Murphy wrote:
> On Tue, Apr 4, 2017 at 4:36 PM, Peter Hutterer <peter.hutterer at who-t.net> wrote:
> > On Tue, Apr 04, 2017 at 12:33:32PM -0600, Chris Murphy wrote:
> >> Before filing a bug...
> >>
> >> I'm having tap to click annoyances. When typing, the cursor insert
> >> point changes somewhere else, and suddenly I'm typing where I don't
> >> want to be; a nearby background application gets "palm tapped" and
> >> becomes foreground. That sort of thing. So it's taken some getting
> >> used to with Fedora 25 but usually I prefer tap to click enabled; but
> >> since upgrading a couple days ago to Fedora 26 which has libinput 1.7
> >> it's gotten much more erratic. The problem stops if I turn off "tap to
> >> click" in gnome-shell preferences. I'm guessing that there's just too
> >> much sensitivity and contact of my thumb palm to the edge surface of
> >> the touchpad is causing this erratic behavior. So I'm curious if
> >> there's a way to make it less sensitive or if there's even a bug here.
> >
> > definitely maybe :) This is something I can't answer without seeing an
> > evemu-record output from such a touch, but that's better attached to a
> > bugreport than email.
> >
> > What I do assume is that the device's pressure values are different to the
> > ranges we set up - that would explain the changes when updating to 1.7.
> > an evemu recording of a few normal one-finger touch sequences will help with
> > that.
> 
> Two captures attached. 30 seconds of normal touching. And a few hours
> that includes palm touches that are causing aberrant behavior.
> 
> https://bugs.freedesktop.org/show_bug.cgi?id=100571

thanks. fwiw, anything that's not easily accessible through batch processing
(e.g. counting things) requires me to replay the events and monitor them in
realtime. So several-hour-long recordings somewhat limit my enthusiasm to do
so :)

for pressure analysis it's easy, but for random things like palm
misdetection I need a really short recording that I can replay over and over
again until the culprit is found.

Cheers,
   Peter