libinput 1.7.0, intermittently erratic touchpad

Chris Murphy lists at
Wed Apr 5 01:05:25 UTC 2017

On Tue, Apr 4, 2017 at 6:25 PM, Peter Hutterer <peter.hutterer at> wrote:
> 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.


$ sudo evemu-record --autorestart=30 /dev/input/event5 scroll.evemu

This doesn't work as I'd expect.

3.7M -rw-r--r--. 1 root  root  3.7M Apr  4 19:04

This is the only file created after 6 minutes. It just keeps on
growing. So I don't understand the effect of autorestart.


Chris Murphy

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