change from xorg evdev driver to libinput driver breaks touchscreen calibration configuration

[Dan Streetman]

when using xorg evdev driver with a touchscreen, it is possible to configure the touchscreen calibration with InputClass options, e.g.:

 Option "MinX" "4128"
 Option "MaxX" "62751"
 Option "MinY" "4075"
 Option "MaxY" "63636"

however, the move to the libinput xorg driver does not use this so upgrades result in touchscreens that no longer are calibrated. Additionally, the normal touchscreen calibration program in Ubuntu, xinput_calibrator, does not work with the libinput xorg driver. This results in a mis/un-calibrated touchscreen, and no way to calibrate it.

[Dan Streetman (ddstreet)]

As a reference, here is one posted workaround:
https://wiki.archlinux.org/index.php/Talk:Calibrating_Touchscreen#Libinput_breaks_xinput_calibrator

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Bert Van de Poel (bhack)]

I had finally convinced an archaeological project I work with to upgrade from Ubuntu 12.04 to a newer version and now our toughbook CF-19 touchscreens can't be calibrated :(

[Dan Streetman (ddstreet)]

> now our toughbook CF-19 touchscreens can't be calibrated

I also use toughbooks, CF-29s and CF-30s, which I think use the same resistive touchscreen as the CF-19s, that requires software calibration. Unfortunately all the cool new tiny (and very delicate) touchscreen tablets and laptops use multi-touch capacitive, which either doesn't require calibration or can do firmware calibration so the OS doesn't need to do software calibration. Toughbooks may be some of the last systems still using (single-touch) resistive touchscreens (as far as I know, because they are far more durable, don't require a delicate glass screen, aren't affected by a dirty screen, and can be used with gloved hands). That is probably why not many people have been affected by this bug.

I had been living with this bug for a long while now because i didn't have time to work on it, but I'll try to find some time in the next few weeks to fix it, if it's affecting others as well. (Unless anyone else wants to fix it first, of course :-)