Use xorg.conf to fix touchscreen X axis reversed

Question

I setup Fedora 35 with my Titan6001 touchscreen. Although Linux is responding to touches, the X axis is reversed (touch on the right mouse goes to left side, and vice versa). Y axis is fine.

How do I reverse this? I'm using X11 (not Wayland)

I created a new xorg.conf using "Xorg -configure" command but it did not contain a section for the Titan6001 (eGalax) device. But I found one on an old post and added it to my xorg.conf as follows:

Section "InputDevice"
    Identifier     "EETI"
    Driver         "egalax"
    Option         "Device" "usbauto"
    Option         "Parameters" "/var/lib/eeti.param"
    Option         "ScreenNo" "0"
    Option         "InvertX" "true"
EndSection

But it made no difference (the InvertX had no effect). I wonder if this section is even being accepted. My Xorg.0.log shows:

  72.646] (II) config/udev: Adding input device eGalax Inc. USB TouchController (/dev/input/event4)
[    72.646] (**) eGalax Inc. USB TouchController: Applying InputClass "evdev touchscreen catchall"
[    72.646] (**) eGalax Inc. USB TouchController: Applying InputClass "libinput touchscreen catchall"
[    72.646] (II) Using input driver 'libinput' for 'eGalax Inc. USB TouchController'
[    72.646] (**) eGalax Inc. USB TouchController: always reports core events
[    72.646] (**) Option "Device" "/dev/input/event4"
[    72.646] (**) Option "_source" "server/udev"
[    72.647] (II) event4  - eGalax Inc. USB TouchController: is tagged by udev as: Touchscreen
[    72.648] (II) event4  - eGalax Inc. USB TouchController: device is a touch device
[    72.648] (II) event4  - eGalax Inc. USB TouchController: device removed
[    72.674] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.0/input/input13/event4"
[    72.674] (II) XINPUT: Adding extended input device "eGalax Inc. USB TouchController" (type: TOUCHSCREEN, id 8)
[    72.674] (**) Option "AccelerationScheme" "none"
[    72.674] (**) eGalax Inc. USB TouchController: (accel) selected scheme none/0
[    72.674] (**) eGalax Inc. USB TouchController: (accel) acceleration factor: 2.000
[    72.674] (**) eGalax Inc. USB TouchController: (accel) acceleration threshold: 4
[    72.676] (II) event4  - eGalax Inc. USB TouchController: is tagged by udev as: Touchscreen
[    72.676] (II) event4  - eGalax Inc. USB TouchController: device is a touch device
[    72.678] (II) config/udev: Adding input device eGalax Inc. USB TouchController (/dev/input/mouse1)

I notice it references mouse1, is that a clue? Should I create a section for that?

So next I tried

xinput --set-prop "eGalax Inc. USB TouchController" "Evdev Axis Inversion" 1, 0

But the property was not recognized. So I tried to list available properties and see:

Device 'eGalax Inc. USB TouchController':
        Device Enabled (142):   1
        Coordinate Transformation Matrix (144): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
        libinput Calibration Matrix (278):      1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
        libinput Calibration Matrix Default (279):      1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
        libinput Send Events Modes Available (261):     1, 0
        libinput Send Events Mode Enabled (262):        0, 0
        libinput Send Events Mode Enabled Default (263):        0, 0
        Device Node (264):      "/dev/input/event4"
        Device Product ID (265):        3823, 1

Can the coordinate transformation matric or input calibration matrix achieve what I want? (Assuming I must set this from the command line, and not xorg.conf)

Answer 1

Yes. Going through this myself. Do not use xinput_calibrate, as it too uses the "old" InvertX, SwapXY, etc, etc. Now all is performed with a transformation matrix, which can handle scale/offset/inversion etc in just one go. I'm learning how to set this up by reading: https://wiki.archlinux.org/title/Talk:Calibrating_Touchscreen