libinput 1.7.0, intermittently erratic touchpad

[Peter Hutterer]

On Tue, Apr 04, 2017 at 07:05:25PM -0600, Chris Murphy wrote:
> On Tue, Apr 4, 2017 at 6:25 PM, Peter Hutterer <peter.hutterer at who-t.net> 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 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.
> >
> 
> Understood.
> 
> $ 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
> scroll.evemu.2017-04-04-18:57:50
> 
> 
> This is the only file created after 6 minutes. It just keeps on
> growing. So I don't understand the effect of autorestart.

autorestart restarts after X seconds of *inactivity*. So you want that time
rather short.

Cheers,
   Peter