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QSerialport did not emit readyRead () signal,but USB monitor data received.Only occasionally problem

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qserialport
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  • J.HilkJ J.Hilk

    @Crawl-W
    please update your Qt version, in 5.12.4 & 5.12.5 and (I think) 5.13.0 & 1. QSerialport is broken, as in it emits not ready read signal

    see
    https://bugreports.qt.io/browse/QTBUG-78086

    Crawl.WC Offline
    Crawl.WC Offline
    Crawl.W
    wrote on last edited by Crawl.W
    #3

    @J-Hilk My version is 5.11.1 and trigger the problem occasionally .

    J.HilkJ 1 Reply Last reply
    0
    • Crawl.WC Crawl.W

      @J-Hilk My version is 5.11.1 and trigger the problem occasionally .

      J.HilkJ Offline
      J.HilkJ Offline
      J.Hilk
      Moderators
      wrote on last edited by
      #4

      @Crawl-W
      well, have you tried/can you try with 5.12.6 ?


      Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


      Q: What's that?
      A: It's blue light.
      Q: What does it do?
      A: It turns blue.

      Crawl.WC 1 Reply Last reply
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      • J.HilkJ J.Hilk

        @Crawl-W
        well, have you tried/can you try with 5.12.6 ?

        Crawl.WC Offline
        Crawl.WC Offline
        Crawl.W
        wrote on last edited by
        #5

        @J-Hilk thks, I try it soon.What's more painful is that it was an accidental event.

        aha_1980A 1 Reply Last reply
        0
        • Crawl.WC Crawl.W

          @J-Hilk thks, I try it soon.What's more painful is that it was an accidental event.

          aha_1980A Offline
          aha_1980A Offline
          aha_1980
          Lifetime Qt Champion
          wrote on last edited by
          #6

          @Crawl-W said in QSerialport did not emit readyRead () signal,but USB monitor data received.Only occasionally problem:

          @J-Hilk thks, I try it soon.What's more painful is that it was an accidental event.

          Well, it might still be a problem in your code. Can you show it?

          Regards

          Qt has to stay free or it will die.

          Crawl.WC 1 Reply Last reply
          0
          • aha_1980A aha_1980

            @Crawl-W said in QSerialport did not emit readyRead () signal,but USB monitor data received.Only occasionally problem:

            @J-Hilk thks, I try it soon.What's more painful is that it was an accidental event.

            Well, it might still be a problem in your code. Can you show it?

            Regards

            Crawl.WC Offline
            Crawl.WC Offline
            Crawl.W
            wrote on last edited by Crawl.W
            #7

            @aha_1980 @J-Hilk yeah,really, there was a problem still.Now, I start to suspect a problem with my code because I use QSerialPort in the GUI thread.
            I found that if there is a slightly longer time interval(more than 3min), the probability of problems is relatively high.But not necessarily.

            aha_1980A 1 Reply Last reply
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            • Crawl.WC Crawl.W

              @aha_1980 @J-Hilk yeah,really, there was a problem still.Now, I start to suspect a problem with my code because I use QSerialPort in the GUI thread.
              I found that if there is a slightly longer time interval(more than 3min), the probability of problems is relatively high.But not necessarily.

              aha_1980A Offline
              aha_1980A Offline
              aha_1980
              Lifetime Qt Champion
              wrote on last edited by
              #8

              @Crawl-W said in QSerialport did not emit readyRead () signal,but USB monitor data received.Only occasionally problem:

              Now, I start to suspect a problem with my code because I use QSerialPort in the GUI thread

              There is nothing wrong with that. I do this all the time.

              There is one problem on Windows though: when you click and hold the mouse button on the window's title bar, the window does not receive events anymore. So if the serial port is in the GUI thread, it will stuck until the mouse is released.

              Regards

              Qt has to stay free or it will die.

              Crawl.WC 1 Reply Last reply
              4
              • aha_1980A aha_1980

                @Crawl-W said in QSerialport did not emit readyRead () signal,but USB monitor data received.Only occasionally problem:

                Now, I start to suspect a problem with my code because I use QSerialPort in the GUI thread

                There is nothing wrong with that. I do this all the time.

                There is one problem on Windows though: when you click and hold the mouse button on the window's title bar, the window does not receive events anymore. So if the serial port is in the GUI thread, it will stuck until the mouse is released.

                Regards

                Crawl.WC Offline
                Crawl.WC Offline
                Crawl.W
                wrote on last edited by
                #9

                @aha_1980 Okay, I will do some checks based on your reminder.Thks!

                1 Reply Last reply
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                • Crawl.WC Offline
                  Crawl.WC Offline
                  Crawl.W
                  wrote on last edited by aha_1980
                  #10

                  @aha_1980 I see another question you answered https://forum.qt.io/topic/94537/qserialport-troubles-on-windows-10/3. My client slowed down also and cpu has been running. My countdown is running normally in the gui thread and highlight effect of minimize button a bit stuck. Just a word, I use QSerialPort in the GUI thread and the program, program always has only one thread, although it has been said before, it is too long. I will go to debug source code further, but if you know what's going on it would be great. The number of threads in this case is 21 which is show in Win10's task mannager.
                  OS : Windows 10 Pro
                  Kit : Qt 5.12.6 msvc2017 64bit
                  Cpu:7700k
                  cpustatus.jpg

                  aha_1980A 1 Reply Last reply
                  0
                  • Crawl.WC Crawl.W

                    @aha_1980 I see another question you answered https://forum.qt.io/topic/94537/qserialport-troubles-on-windows-10/3. My client slowed down also and cpu has been running. My countdown is running normally in the gui thread and highlight effect of minimize button a bit stuck. Just a word, I use QSerialPort in the GUI thread and the program, program always has only one thread, although it has been said before, it is too long. I will go to debug source code further, but if you know what's going on it would be great. The number of threads in this case is 21 which is show in Win10's task mannager.
                    OS : Windows 10 Pro
                    Kit : Qt 5.12.6 msvc2017 64bit
                    Cpu:7700k
                    cpustatus.jpg

                    aha_1980A Offline
                    aha_1980A Offline
                    aha_1980
                    Lifetime Qt Champion
                    wrote on last edited by
                    #11

                    Hi @Crawl-W,

                    no unfortunately I don't know what's going on.

                    And as you cannot share your code, it's just guessing from my side.

                    So the best tip I can give you: Minimize your program. Generate reproduciable test cases. Use tools like profilers or timestamp logging to find the places that eat your CPU.

                    Good luck, regards

                    Qt has to stay free or it will die.

                    1 Reply Last reply
                    1
                    • Crawl.WC Offline
                      Crawl.WC Offline
                      Crawl.W
                      wrote on last edited by
                      #12

                      @aha_1980 I found QIODevice::readyRead eat my cpu, but I am still not know why. This usually happens in a pop-up dialog to let the user confirm an action and the user waits for a while to do it. The serial port was not actively disconnected during the period, and of course it was not reconnected, just continue to send command to the equipment. From the cpu curve, I suspect the effect of the timer.
                      bug.jpg

                      J.HilkJ 1 Reply Last reply
                      0
                      • Crawl.WC Crawl.W

                        @aha_1980 I found QIODevice::readyRead eat my cpu, but I am still not know why. This usually happens in a pop-up dialog to let the user confirm an action and the user waits for a while to do it. The serial port was not actively disconnected during the period, and of course it was not reconnected, just continue to send command to the equipment. From the cpu curve, I suspect the effect of the timer.
                        bug.jpg

                        J.HilkJ Offline
                        J.HilkJ Offline
                        J.Hilk
                        Moderators
                        wrote on last edited by
                        #13

                        @Crawl-W said in QSerialport did not emit readyRead () signal,but USB monitor data received.Only occasionally problem:

                        I found QIODevice::readyRead eat my cpu, but I am still not know why. This usually happens in a pop-up dialog to let the user confirm an action and the user waits for a while to do it.

                        No. Popup dialogs do not consume cpu. If your (Qt)program does, then you're doing something wrong. Most likely blocking while loops and manual event loop spinning or QEventLoop uses.
                        Stuff like that, and one isn't supposed to do...


                        Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                        Q: What's that?
                        A: It's blue light.
                        Q: What does it do?
                        A: It turns blue.

                        Crawl.WC 1 Reply Last reply
                        1
                        • J.HilkJ J.Hilk

                          @Crawl-W said in QSerialport did not emit readyRead () signal,but USB monitor data received.Only occasionally problem:

                          I found QIODevice::readyRead eat my cpu, but I am still not know why. This usually happens in a pop-up dialog to let the user confirm an action and the user waits for a while to do it.

                          No. Popup dialogs do not consume cpu. If your (Qt)program does, then you're doing something wrong. Most likely blocking while loops and manual event loop spinning or QEventLoop uses.
                          Stuff like that, and one isn't supposed to do...

                          Crawl.WC Offline
                          Crawl.WC Offline
                          Crawl.W
                          wrote on last edited by
                          #14

                          @aha_1980 @J-Hilk First of all, I need to clarify that the software I maintain now is really suck. I most likely have solved this problem and now the program runs well.

                          I need to describe the process of this problem:
                          1.QTextEdit becomes stuck slowly because of appending so many messages
                          2.a dialog pops up(exec()), after confirmation then update tableview viewport with QTableView::viewport()->update()
                          3.click a button continue to R/W serial port.

                          I originally suspected it was due to QTableView::viewport()->update(), which schedules a paint event for processing when Qt returns to the main event loop. However, my experiment found QTextEdit's stuck lead the QSerialport did not emit readyRead () signal.

                          Why?
                          thanks you guys for patience all the time.

                          aha_1980A J.HilkJ 2 Replies Last reply
                          2
                          • Crawl.WC Crawl.W

                            @aha_1980 @J-Hilk First of all, I need to clarify that the software I maintain now is really suck. I most likely have solved this problem and now the program runs well.

                            I need to describe the process of this problem:
                            1.QTextEdit becomes stuck slowly because of appending so many messages
                            2.a dialog pops up(exec()), after confirmation then update tableview viewport with QTableView::viewport()->update()
                            3.click a button continue to R/W serial port.

                            I originally suspected it was due to QTableView::viewport()->update(), which schedules a paint event for processing when Qt returns to the main event loop. However, my experiment found QTextEdit's stuck lead the QSerialport did not emit readyRead () signal.

                            Why?
                            thanks you guys for patience all the time.

                            aha_1980A Offline
                            aha_1980A Offline
                            aha_1980
                            Lifetime Qt Champion
                            wrote on last edited by
                            #15

                            @Crawl-W

                            However, my experiment found QTextEdit's stuck lead the QSerialport did not emit readyRead () signal.

                            I can only think of problems if both are in the same thread, and maybe the event loop does not run anymore when you edit gets too slow.

                            Anyway, glad you solved it!

                            Regards

                            Qt has to stay free or it will die.

                            1 Reply Last reply
                            0
                            • Crawl.WC Crawl.W

                              @aha_1980 @J-Hilk First of all, I need to clarify that the software I maintain now is really suck. I most likely have solved this problem and now the program runs well.

                              I need to describe the process of this problem:
                              1.QTextEdit becomes stuck slowly because of appending so many messages
                              2.a dialog pops up(exec()), after confirmation then update tableview viewport with QTableView::viewport()->update()
                              3.click a button continue to R/W serial port.

                              I originally suspected it was due to QTableView::viewport()->update(), which schedules a paint event for processing when Qt returns to the main event loop. However, my experiment found QTextEdit's stuck lead the QSerialport did not emit readyRead () signal.

                              Why?
                              thanks you guys for patience all the time.

                              J.HilkJ Offline
                              J.HilkJ Offline
                              J.Hilk
                              Moderators
                              wrote on last edited by
                              #16

                              @Crawl-W said in QSerialport did not emit readyRead () signal,but USB monitor data received.Only occasionally problem:

                              QTextEdit's

                              have you tried setting the undoRedo property to false ? That's usually a high performance eater when one appends (a lot) to the textedit

                              setUndoRedoEnabled(false);

                              the default is true


                              Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                              Q: What's that?
                              A: It's blue light.
                              Q: What does it do?
                              A: It turns blue.

                              Crawl.WC 1 Reply Last reply
                              1
                              • J.HilkJ J.Hilk

                                @Crawl-W said in QSerialport did not emit readyRead () signal,but USB monitor data received.Only occasionally problem:

                                QTextEdit's

                                have you tried setting the undoRedo property to false ? That's usually a high performance eater when one appends (a lot) to the textedit

                                setUndoRedoEnabled(false);

                                the default is true

                                Crawl.WC Offline
                                Crawl.WC Offline
                                Crawl.W
                                wrote on last edited by
                                #17

                                @J-Hilk Tks, I will do a test. Btw, I want to know more the root cause of QSerialport did not emit readyRead () signal.

                                1 Reply Last reply
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