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my app blinking on ubuntu

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  • mmjvoxM Offline
    mmjvoxM Offline
    mmjvox
    wrote on last edited by mmjvox
    #1

    0_1568544025415_aaa.gif

    my app blinking sometimes without any known reason or any bug in my code
    This problem only happens to Ubuntu 16 or older
    and No problem on other distros or windows
    and i tested it on many machines with qt 5.12.0 , 5.12.2 , 5.12.4

    what's the solution?

    1 Reply Last reply
    0
    • SGaistS Offline
      SGaistS Offline
      SGaist
      Lifetime Qt Champion
      wrote on last edited by
      #2

      Hi,

      Did you test your application using your distribution provided Qt ?

      Interested in AI ? www.idiap.ch
      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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      • mmjvoxM Offline
        mmjvoxM Offline
        mmjvox
        wrote on last edited by
        #3

        yes i build it again with 5.12.2 kit provided by ubuntu for xenial ... but It didn't make a difference
        and today i tested on 5.12.5 with some fixes about blinking that listed in qt bugreports ... but It didn't make a difference too.

        i found it that blinks are much scary when app is in full screen

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        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #4

          Does a default sample application exhibit the same behaviour ?

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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          • mmjvoxM Offline
            mmjvoxM Offline
            mmjvox
            wrote on last edited by mmjvox
            #5

            yes but not always, sometimes even on a simple app with some listview or gridview that each one have many items

            There is also a possibility that this is a problem with my code, but the suspicious thing that exists is that, the behaviour only is on ubuntu 16.04 (i tested on unity desktop and xfce and cinnamon and gnome3)

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            • SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on last edited by
              #6

              Well, if even the distribution provided Qt exhibits that behaviour, then there might be something in your installation. What graphics card are you using ?

              Interested in AI ? www.idiap.ch
              Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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              • mmjvoxM Offline
                mmjvoxM Offline
                mmjvox
                wrote on last edited by
                #7

                yes you'r right it may be a problem with the graphics driver..
                all of computers that i installed ubuntu and tested my app (even new build on that) had old nvidia (2 old card with nouveau) and intel graphics (i3 4th gen , i3 5th gen, i5 5th gen,i7 1th gen ) ...
                and all of other distros i tested had amd cards and new intel graphics ..

                last night i installed my app on an ubuntu16.04 virtual machin (virtualbox and kvm) , I didn't see any blinks.

                If there is a problem with the graphics card or the graphics driver , What is the best solution to the problem?
                all users using this app dont have the ability to install new drivers or buy another cards.

                K 1 Reply Last reply
                0
                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #8

                  On how many machines di you saw that behaviour ?

                  What kernel were they running ?

                  Interested in AI ? www.idiap.ch
                  Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                  mmjvoxM 1 Reply Last reply
                  0
                  • mmjvoxM mmjvox

                    yes you'r right it may be a problem with the graphics driver..
                    all of computers that i installed ubuntu and tested my app (even new build on that) had old nvidia (2 old card with nouveau) and intel graphics (i3 4th gen , i3 5th gen, i5 5th gen,i7 1th gen ) ...
                    and all of other distros i tested had amd cards and new intel graphics ..

                    last night i installed my app on an ubuntu16.04 virtual machin (virtualbox and kvm) , I didn't see any blinks.

                    If there is a problem with the graphics card or the graphics driver , What is the best solution to the problem?
                    all users using this app dont have the ability to install new drivers or buy another cards.

                    K Offline
                    K Offline
                    kkuzawska
                    wrote on last edited by
                    #9

                    @mmjvox
                    If it's nvidia case -maybe try switching between non-threaded and threaded render loop. I had similar problem on my app and it helped me a lot . I had to set QSG_RENDER_LOOP enviroment variable to "basic" to get rid of blinking effect.
                    You can do this simply by adding this line to your main.cpp code before calling app.exec() :
                    qputenv("QSG_RENDER_LOOP","basic");
                    or when it not helps try: qputenv("QSG_RENDER_LOOP","threaded");

                    It's just my idea - setting enviroment variables for QSG helped me when developing apps on computers with different graphic cards.

                    mmjvoxM 2 Replies Last reply
                    1
                    • SGaistS SGaist

                      On how many machines di you saw that behaviour ?

                      What kernel were they running ?

                      mmjvoxM Offline
                      mmjvoxM Offline
                      mmjvox
                      wrote on last edited by
                      #10

                      @SGaist
                      on 7 or 8 machins
                      ubuntu default kernel (4.4 , 4.10, 4.11, 4.15)

                      1 Reply Last reply
                      0
                      • K kkuzawska

                        @mmjvox
                        If it's nvidia case -maybe try switching between non-threaded and threaded render loop. I had similar problem on my app and it helped me a lot . I had to set QSG_RENDER_LOOP enviroment variable to "basic" to get rid of blinking effect.
                        You can do this simply by adding this line to your main.cpp code before calling app.exec() :
                        qputenv("QSG_RENDER_LOOP","basic");
                        or when it not helps try: qputenv("QSG_RENDER_LOOP","threaded");

                        It's just my idea - setting enviroment variables for QSG helped me when developing apps on computers with different graphic cards.

                        mmjvoxM Offline
                        mmjvoxM Offline
                        mmjvox
                        wrote on last edited by
                        #11

                        @kkuzawska
                        thanks
                        i will test it today

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                        0
                        • JoeCFDJ Offline
                          JoeCFDJ Offline
                          JoeCFD
                          wrote on last edited by
                          #12

                          https://ubuntuforums.org/showthread.php?t=2061180

                          1 Reply Last reply
                          0
                          • K kkuzawska

                            @mmjvox
                            If it's nvidia case -maybe try switching between non-threaded and threaded render loop. I had similar problem on my app and it helped me a lot . I had to set QSG_RENDER_LOOP enviroment variable to "basic" to get rid of blinking effect.
                            You can do this simply by adding this line to your main.cpp code before calling app.exec() :
                            qputenv("QSG_RENDER_LOOP","basic");
                            or when it not helps try: qputenv("QSG_RENDER_LOOP","threaded");

                            It's just my idea - setting enviroment variables for QSG helped me when developing apps on computers with different graphic cards.

                            mmjvoxM Offline
                            mmjvoxM Offline
                            mmjvox
                            wrote on last edited by
                            #13

                            @kkuzawska

                            It didn't solve :D

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                            0
                            • mmjvoxM Offline
                              mmjvoxM Offline
                              mmjvox
                              wrote on last edited by
                              #14

                              finaly
                              I found out that the problem was with Intel drivers and update the kernel solved the problem.

                              1 Reply Last reply
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