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

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.