Lightdm service fails to start after installing DSI connected screen drivers (Edatec, Waveshare)

[mgrouch]

Lightdm service fails to start after installing DSI connected screen drivers

users reported it as an issue with edatec
ED-HMI3020-101C

Waveshare DSI LCD

See also
#327 (reply in thread)

[mgrouch]

[mgrouch]

Also

https://www.cruisersforum.com/forums/f134/recommended-cockpit-platform-285146-10.html#post3896976

[mgrouch]

Per Edatec support after the following changes lightdm starts:

removed /etc/udev/rules.d/99-uinput.rules and modified /usr/share/X11/xorg.conf.d/90-touchinput.conf

user@lysmarine:~ $ cat /usr/share/X11/xorg.conf.d/90-touchinput.conf
Section "InputClass"
    Identifier "calibration"
    Driver "evdev"
    MatchProduct "4-0014 Goodix Capacitive TouchScreen gt911 Synopsys DesignWare I2C adapter"
    MatchDevicePath "/dev/input/event*"
    Option "EmulateThirdButton" "1"
    Option "EmulateThirdButtonTimeout" "750"
    Option "EmulateThirdButtonMoveThreshold" "30"
EndSection

[mgrouch]

Regarding Waveshare DSI touchscreen issues

here is a thread on raspberry pi forums:

https://forums.raspberrypi.com/viewtopic.php?t=366011

[mgrouch]

Rotating DSI display discussion

https://forums.raspberrypi.com/viewtopic.php?t=369626

best way to tell X that the desktop should be rotated is via

xrandr --output DSI-1 --rotate left

or similar

[mgrouch]

Regarding screen rotation on Edatec

Look for CalibrationMatrix

https://www.cruisersforum.com/forums/f134/cant-install-opencpn-on-rpi5-286085.html#post3899802

[mgrouch]

Edatec support was able to solve all issues with their touchscreen on BBN OS:

Hi Mikhail,

I've solved the problem of twofing not working.

It needs to modify “/usr/share/X11/xorg.conf.d/90-touchinput.conf”

Section "InputClass"
    Identifier "calibration"
    Driver "evdev"
    MatchProduct "Goodix Capacitive TouchScreen"
    MatchDevicePath "/dev/input/event*"
    Option "EmulateThirdButton" "1"
    Option "EmulateThirdButtonTimeout" "750"
    Option "EmulateThirdButtonMoveThreshold" "30"
    Option "Calibration" "0 1280 0 800"
    Option "SwapAxes" "1"
    Option "Inversion" "1 0"
EndSection

[mgrouch]

More on DSI displays

raspberrypi/linux#6341