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QSerialPort::readyRead not emitting for specific USB adapter after compiling

  • I'm having a weird problem where I'm not getting a readyRead signal from a specific USB serial adapter when I build and test a program with QT Creator 4.3.1 and Qt 5.9.1. I first encountered this error in my own program and after trying to troubleshoot it for a few hours I'm out of ideas.

    If I open the troublesome device with CuteCom 0.30.3 from kubuntu's repo it works as expected. But if I compile the latest CuteCom from Github it won't work. Both versions of CuteCom and my own program work fine with an Arduino I programmed to simulate the expected output of the device I'm trying to interface with.

    In my own program I output the serial->error() and serial->errorString() over qDebug() but they don't show any problems.

    I've never had any problems with the adapter before. Here is what it is for reference though: http://a.co/ifMxByq

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    As I can see from your link, this is PL-2303 based chip. If so, then there shouldn't be problems. Maybe it is related to QTBUG-48304? But maybe your device just a broken.

  • The device works just fine with any other software. I've used it with PySide, screen, and CuteCom from the kubuntu repo. It only fails on software that I compiled in QT Creator.

    I am on linux and have been needing to try compiling this on Windows. I'll test that in a bit and see if it works then.

    I'm not sure if that kernel bug would be it, but I'll give upgrading my kernel a shot at fixing it.

  • My software and the Terminal example don't work in Windows as well when complied with Qt Creator 4.3.1 and Qt 5.9.1.

    Here is the adapter working with RealTerm to demonstrate that it does work:
    alt text

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