Re: v4.1 to v4.7: regression in tsc2005 driver

Pavel Machek
2016-07-20T20:22:08Z

Hi!

> > > > > > > > > drivers/input/touchscreen/tsc2005.c: input_dev->name = "TSC2005
> > > > > > > > > touchscreen";
> > > > > > > > >
> > > > > > > > > to "TSC200X touchscreen". Unfortunately, X seems to propagate that
> > > > > > > > > name to userspace, where it is needed to be able to do
> > >
> > > Technically X _is_ userspace.
> >
> > There's "userspace running as root" and "userspace userspace" :-).
>
> I do not really see any difference form the kernel POW.
>
> >
> > > > > > > > >
> > > > > > > > > xinput --set-prop --type=int ...
> > > > > > > > >
> > > > > > > > > with the right arguments to calibrate touchscreen. (Touchscreen is
> > > > > > > > > unusable without calibration).
> > > > > > > > >
> > > > > > > > > What to do with that?
> > >
> > > Hmm, I do not think we ever committed for the device names to be stable.
> > > You are supposed to locate touchscreen device based on its properties
> > > and you might need some heuristic if you encounter a system with more
> > > than one such touchscreen.
> >
> > Well, you are commited now, like it or not, X people did it for you
> > :-(.
> >
> > Because there's no other reasonable way to use xinput --set-prop...
>
> Well, X is going to have to fix it. How am I supposed to control my
> devices in multi-seat environment if I use the same hardware (or if I
> have device with multiple touchscreens)? They all will have the same
> name (well, all mice, then all keyboards, etc). Let's add Peter to the
> fold...

Well, if someone has such a multiseat config, they have a problem. But
in the meantime, I'd like to keep working system.

http://who-t.blogspot.cz/2016/07/xinput-resolves-device-names-and.html

And I see you replied in the blog. Good. Yes, X needs to be improved
to work nicely with multiseat. Still kernel needs to play nice and not
have regressions.
Pavel
--
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(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html