Raspberry Pi 4 touchscreen with Qt5.15 embedded is not working

[Ronel_qtmaster]

you need to install drivers for your touch screen

[Axel Spoerl]

@Ronel_qtmaster I think @Alexey_Golubev has installed the drivers here

apt-get install evtest libts-bin
apt-get install libts-dev

@Alexey_Golubev
ts_calibrate and ts_test have meaningful outputs, and the TS works e.g. hooked up to a PC.

Touchscreen not working.

What's not working? Display? Touch? Both?

export QT_QPA_EVDEV_TOUCHSCREEN_PARAMETERS=/dev/input/event1

=> what is intended here? I use this env variable for parameters, e.g. /dev/input/event1:rotate=180
IMHO, you don't have to pass anything here, unless you want to pass a parameter.

[Alexey_Golubev]

@Axel-Spoerl said in Raspberry Pi 4 touchscreen with Qt5.15 embedded is not working:

ts_calibrate and ts_test have meaningful outputs, and the TS works e.g. hooked up to a PC.

ts_calibrate and ts_test output correct data. When connected to a PC, the touch works correctly.

@Axel-Spoerl said in Raspberry Pi 4 touchscreen with Qt5.15 embedded is not working:

What's not working? Display? Touch? Both?

The touchscreen is not working. The display is working.
When running the qt 5.15 program, the display works. The touchscreen doesn't work.

[Axel Spoerl]

Which XInput driver are you using? libinput (wrong), or evdev(right).

[Alexey_Golubev]

@Axel-Spoerl said in Raspberry Pi 4 touchscreen with Qt5.15 embedded is not working:

evdev(right)

I installed it first evdev:
sudo apt-get install xserver-xorg-input-evdev

change the driver in a config file:
sudo nano /usr/share/X11/xorg.conf.d/40-libinput.conf

at the lines with touchscreen driver replace libinput by evdev

  Section "InputClass"
      Identifier "evdev tablet catchall"
      MatchIsTablet "on"
      MatchDevicePath "/dev/input/event*"
      Driver "evdev"
  EndSection

[Axel Spoerl]

Hm, that looks just fine.
The only thing left would be to try /dev/input/event0 and /dev/input/event2 respectively.
Maybe the "stylus" device reacts only to a pen.

[Alexey_Golubev]

@Axel-Spoerl said in Raspberry Pi 4 touchscreen with Qt5.15 embedded is not working:

The only thing left would be to try /dev/input/event0 and /dev/input/event2 respectively.

How can this be done? You can learn more for beginners.

[Axel Spoerl]

To begin with, you're not a beginner, @Alexey_Golubev ;-)

Replace this

export TSLIB_TSDEVICE=/dev/input/event1

and try this

export TSLIB_TSDEVICE=/dev/input/event0

and this

export TSLIB_TSDEVICE=/dev/input/event2

[Alexey_Golubev]

if export TSLIB_TSDEVICE=/dev/input/event1 that ts_calibrate work.
if export TSLIB_TSDEVICE=/dev/input/event0 that ts_calibrate notwork.
if export TSLIB_TSDEVICE=/dev/input/event2 that ts_calibrate notwork.

[Alexey_Golubev]

@Axel-Spoerl said in Raspberry Pi 4 touchscreen with Qt5.15 embedded is not working:

export TSLIB_TSDEVICE=/dev/input/event1

What should I do next?

[Axel Spoerl]

I am kinda lost.
Maybe try Qt 6, even though I wouldn't know of a long standing bug that prevents touch from working.

[Alexey_Golubev]

@Axel-Spoerl said in Raspberry Pi 4 touchscreen with Qt5.15 embedded is not working:

I wouldn't know of a long standing bug that prevents touch from working

I can't use Qt6.
Maybe you need special keys for qt 5.15?

[Alexey_Golubev]

@Axel-Spoerl said in Raspberry Pi 4 touchscreen with Qt5.15 embedded is not working:

I am kinda lost.

Can you help?

[Axel Spoerl]

No, I have no more ideas.

[Alexey_Golubev]

@Axel-Spoerl said in Raspberry Pi 4 touchscreen with Qt5.15 embedded is not working:

No, I have no more ideas.

I found that "-plugin tslib" touchscreen works.
"export QT_QPA_FB_TSLIB=1" does not work.
If I write "root@pi:~# /home/pi/Qt_Projects/kiab/kia -plugin tslib" then the touchscreen works.