[SOLVED] Running Qt/QtQuick 5.1 application (eglfs platform) with different color depth compared to the linux framebuffer



  • Hi,

    I would like to run Qt/Quick applications using a 24-bit LCD which is connected to the lvds serializer but I have a problem with displaying colors on my embedded device (AM335x) using linux kernel version 3.2, qt version 5.1 and eglfs platform. The problem is that the color depth of the linux framebuffer must be set to 32-bit (ARGB88888) mode because graphical driver (SGX-PVR) does not not support the RGB888 mode of the LCD. Is there a way that I can run Qt 5.1 applications using 24 bit color depth on the 32 bit framebuffer?

    I've also run my applications using QT_QPA_EGLFS_FORCE888 and QT_QPA_EGLFS_DEPTH env. variables as it is explained "here":http://doc-snapshot.qt-project.org/qt5-dev/embedded-linux.html with the same result - it is possible that version 5.1 of qt library does not support this (?).

    Kind regards,

    Georgije Bosiger


  • Lifetime Qt Champion

    Hi and welcome to devnet,

    For such a low-level question you should post this question on the interest mailing list. You'll find there Qt's developers/maintainers (this forum is more user oriented)



  • Thank you. I'll do that next time.
    I've realiezed that the the 24 bit LCD can work without any problems on the 32 bit frame buffer because the way the data is stored and read by the LCD controller. The issue with the colors is related to the panel setings in the kernel. Problem is solved.


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