libinput 1.7.0, intermittently erratic touchpad

Peter Hutterer peter.hutterer at
Wed Apr 5 00:25:10 UTC 2017

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> 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.

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.


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