Touchscreen calibration

[jordi-s]

Greetings,

I had some success calibrating the screen with the following procedure:

• Run xinput_calibration -v
• Add the section that xinput_calibration suggests to /usr/share/X11/xorg.conf.d/99-calibration.conf. Also take note of the coordinates of points 0 (x0, y0) and point 3 (x3, y3) as given by xinput_calibration.
• Now leave as the only option in that section Option "CalibrationMatrix" "a 0 c 0 e f 0 0 1" where numbers a, c, e and f are calculated as follows
  width=1920
height=1200
a = (width * 6 / 8) / (x3 - x0)
c = ((width / 8) - (a * x0)) / width
e = (height * 6 / 8) / (y3 - y0)
f = ((height / 8) - (e * y0)) / height
  For example, in my case the result was
  Option "CalibrationMatrix" "2.0571 0 0.005 0 -2.7108 0.99247 0 0 1"

That is enough to make the touchscreen work more or less, depending on the accuracy of the input when running xinput_calibration

I hope that it helps!

[junocomp]

Did you try this on Ubuntu 18.04?

[jordi-s]

Yes (Kubuntu 18.04 to be precise, installed on the i15-TD model), but I suppose that it can be applied to any recent x.org install.

[jordi-s]

I attach my configuration file just in case it is useful:
99-calibration.conf.zip

[junocomp]

Thank you. Which touch driver did you use? Can you share that as well please.

[jordi-s]

I am not sure if I obtained the driver in the same way as described in this repository.

First, I obtained the SileadTouch.sys windows driver. Then, with the following perl script I extracted a file that was automatically named firmware_00.fw. I renamed it to mssl1680.fw and copied it to /lib/firmware/silead/mssl1680.fw. After reboot, I had the touchscreen recognized, but without calibration.