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Forum Update on Monday, May 27th 2025

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

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  • A Offline
    A Offline
    Alexey_Golubev
    wrote on 30 May 2024, 00:53 last edited by Alexey_Golubev
    #6

    @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
    
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    • A Offline
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      Axel Spoerl
      Moderators
      wrote on 30 May 2024, 08:25 last edited by
      #7

      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.

      Software Engineer
      The Qt Company, Oslo

      A 1 Reply Last reply 30 May 2024, 08:33
      0
      • A Axel Spoerl
        30 May 2024, 08:25

        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.

        A Offline
        A Offline
        Alexey_Golubev
        wrote on 30 May 2024, 08:33 last edited by
        #8

        @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.

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        • A Offline
          A Offline
          Axel Spoerl
          Moderators
          wrote on 30 May 2024, 08:37 last edited by
          #9

          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
          

          Software Engineer
          The Qt Company, Oslo

          A 1 Reply Last reply 30 May 2024, 09:23
          0
          • A Offline
            A Offline
            Alexey_Golubev
            wrote on 30 May 2024, 08:48 last edited by Alexey_Golubev
            #10

            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.
            1.png

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            • A Axel Spoerl
              30 May 2024, 08:37

              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
              
              A Offline
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              Alexey_Golubev
              wrote on 30 May 2024, 09:23 last edited by
              #11

              @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?

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              • A Offline
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                Axel Spoerl
                Moderators
                wrote on 30 May 2024, 10:56 last edited by
                #12

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

                Software Engineer
                The Qt Company, Oslo

                A 2 Replies Last reply 30 May 2024, 13:12
                0
                • A Axel Spoerl
                  30 May 2024, 10:56

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

                  A Offline
                  A Offline
                  Alexey_Golubev
                  wrote on 30 May 2024, 13:12 last edited by
                  #13

                  @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?

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                  • A Axel Spoerl
                    30 May 2024, 10:56

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

                    A Offline
                    A Offline
                    Alexey_Golubev
                    wrote on 31 May 2024, 07:24 last edited by
                    #14

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

                    I am kinda lost.

                    Can you help?

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                    • A Offline
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                      Axel Spoerl
                      Moderators
                      wrote on 31 May 2024, 09:42 last edited by
                      #15

                      No, I have no more ideas.

                      Software Engineer
                      The Qt Company, Oslo

                      A 1 Reply Last reply 4 Jun 2024, 13:29
                      0
                      • A Axel Spoerl
                        31 May 2024, 09:42

                        No, I have no more ideas.

                        A Offline
                        A Offline
                        Alexey_Golubev
                        wrote on 4 Jun 2024, 13:29 last edited by Alexey_Golubev 6 Apr 2024, 13:32
                        #16

                        @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.

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                        31 May 2024, 09:42

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