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Helping in calibrating etp-4500ug for working in RPI3

  • Hi
    I write a program with QT5.7 and cross compile to RPI3 . I use eglfs .
    I'm using an eGalax touchscreen(etp-4500ug) , trying to get it to work with Raspberry Pi and Qt5. it sounds like it needs to work with tslib. Touch is working but it is mirrored.
    I've been able to get tslib to work with this display using a tarball and two patches from:
    I have set the following environment variables:

    When I run ts_calibrate I get the "Segmentation fault" error.

    By regards

  • Lifetime Qt Champion

    Hi and welcome to devnet,

    As silly as it may sound, run ts_calibrate through a debugger to see what's going wrong.

  • Hi and Thanks you for reply
    I connect to raspberry through ssh and run ts_calibrate and get the "Segmentation fault" message .
    Recently I use below variable for TSLIB

     export LD_LIBRARY_PATH=/usr/local/qt5pi/lib
     export PATH=/usr/local/qt5pi/bin:$PATH
    # hides mouse cursor
     # enables tslib plugin for touch screen
     export QT_QPA_GENERIC_PLUGINS=Tslib
     # disables evdev mouse input (to avoid getting duplicated input from tslib AND evdev)
     export TSLIB_FBDEVICE=/dev/fb0
     export TSLIB_CONSOLEDEVICE=none
     export TSLIB_TSDEVICE=/dev/input/by-id/`ls /dev/input/by-id/ | grep "eGalax"`
     export TSLIB_CONFFILE=/etc/ts.conf
     export TSLIB_CALIBFILE=/etc/pointercal
     export TSLIB_PLUGINDIR=/usr/lib/arm-linux-gnueabihf/ts0

    But with the same error "Segmentation fault" ...


  • Lifetime Qt Champion

    Like I wrote before, run it through the debugger. You can install gdb on your Pi.

  • I install QT5.7 on ubuntu on vmware and cross compile it to the Pi and I can debug my program through it. Do you mean this?

  • I got what you say . But is a new project for me :-)
    I want to solve this problem easier than this.

  • Qt Champions 2019

    @tictactoe If you really do not want to use a debugger (this is actually something a programmer should learn) you can add qDebug() << "..." to your code at the places where you think the problem occurs. This can help to find out where the crash happens. But it isn't really easier than just using a debugger, which isn't rocket science.

  • I dont have any problem during on the running of my program . The only problem is the swapping the axes of X,Y of the touch controller.
    I want to solve it

  • finally I cant run ts_calibrate and save calibration point in the /etc/pointercal .
    The below list is the last updated of environment variable for tslib and eglfs

    export QT_QPA_PLATFORM=eglfs
    export QT_QPA_EGLFS_TSLIB=1
    export QT_QPA_EGLFS_TOUCHSCREEN_PARAMETERS=/dev/input/event0:invertx=1
    export TSLIB_FBDEVICE=/dev/fb0
    export TSLIB_CONSOLEDEVICE=/dev/tty
    export TSLIB_TSDEVICE=/dev/input/by-id/ls /dev/input/by-id/ | grep "eGalax"
    export TSLIB_CONFFILE=/etc/ts.conf
    export TSLIB_CALIBFILE=/etc/pointercal
    export TSLIB_PLUGINDIR=/usr/local/lib/ts

    I dont know about the "QT_QPA_GENERIC_PLUGINS" variable.
    I have a problem of inverting the X axis in my QT program that run on RPI3 yet
    how can I solve this?


  • @SGaist
    I want to install gdb on RPI as you said before.
    I want to use the below link for installing gdb on rpi and ubuntu. Is it correct ?

    link text


  • Lifetime Qt Champion

    Does look good yes

  • I dont know how to debug my qt program with gdb. Can you give me link for this?

  • Lifetime Qt Champion

    It's the same as any other program. Note that you can remote debug from Qt Creator. It's explained in the Launching the Debugger chapter of Qt Creator's documentation.

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