Configure touchpad for touchscreen driver

[Peter Hutterer]

On Fri, May 05, 2017 at 05:30:51PM +0200, Martin Kepplinger wrote:
> Hi,
> 
> I'm doing a touchscreen xorg input driver. 

First question: why? :)
we generally discourage people from doing that, instead it's better to write
a kernel driver and use the existing evdev/libinput drivers.

> For testing purposes, I'd like to configure my laptop's touchpad for the
> driver to use. It's totally comparable and I've done it for other stuff
> for rough testing. I append the evtest output below. Should be fine.
> 
> I'm unsure how to override all other touchpad configs in my system.
> 
>  * is it enough to say "MatchIsTouchpad" instead of touchscreen? There's
> obviously only one touchpad. Ideally I think I should omit
> "MatchIsTouchpad" and say only "Device=/dev/input/event1" or whatever
> number it is? Would that be possible?

MatchIsTouchpad maps to the udev property ID_INPUT_TOUCHPAD, your homework
is to figure out what MatchIsTouchscreen maps to ;)
so doing that would be enough, but you could also add a
MatchProduct "ETPS/2 Elantech Touchpad" to only match on that touchpad.

Don't match on device nodes as they can change during reboots.

>  * My driver config installs to /usr/local/share/X11/... Will this
> *ever* override /usr/share/X11 configs? Even if I call it
> "00-mydriver.conf" in /usr/local/

the server is usually configured to look into /usr/share/X11/ and /etc/X11,
but not elsewhere. So anything you put in /usr/local is ignored. The start
of the xorg.log should list where the server is looking for configs.

for local configurations, you're supposed to put them into /etc/ anyway,
distribution-provided config snippets go into /usr/local.

Cheers,
   Peter