Could not initialize egl display on Embedded Linux



  • Hello,
    I'm attempting to port an application to a new platform running Linux kernel 4.14, Debian 10, and Qt 5.12.3
    My application compiles successfully on the target platform and runs using the LinuxFB plugin, but using the EGLFS plugin results in the following message: "Could not initialize egl display".

    I've tried setting QT_QPA_EGLFS_INTEGRATION=none, but that didn't work.

    The embedded system uses a Qualcomm Snapdragon 8xx series processor.
    Qt has been configured with the following QPA backends:

     DirectFB ............................... no
     EGLFS .................................. yes
     EGLFS details:
       EGLFS OpenWFD ........................ no
       EGLFS i.Mx6 .......................... no
       EGLFS i.Mx6 Wayland .................. no
       EGLFS RCAR ........................... no
       EGLFS EGLDevice ...................... yes
       EGLFS GBM ............................ no
       EGLFS VSP2 ........................... no
       EGLFS Mali ........................... no
       EGLFS Raspberry Pi ................... no
       EGLFS X11 ............................ yes
     LinuxFB ................................ yes
     VNC .................................... yes
     Mir client ............................. no
     XCB:
       Using system-provided XCB libraries .. no
       XCB XKB .............................. yes
       XCB XInput ........................... yes
       Native painting (experimental) ....... no
       GL integrations:
         GLX Plugin ......................... no
         EGL-X11 Plugin ..................... yes
    

    Is there anything else I can try?

    Thanks,
    David


  • Lifetime Qt Champion

    Hi and welcome to devnet,

    Can you give more details about that device ?
    Can your other applications that uses EGLFS ?



  • Hello,
    The embedded system is a Snapdragon 820. The debian installation is based on Linaro's Debian image for the Dragonboard 820C.

    https://github.com/fhunleth/qt-rectangles has the same issue when compiled for Qt 5.12.
    The same program works fine when compiled against Debian 10's precompiled Qt 5.11 libraries.
    I must be doing something wrong when configuring the Qt 5.12 installation, but I'm not sure what that something could be.



  • My application also runs correctly under Qt 5.11 using EGLFS.
    Normally I would consider downgrading to 5.11, but my company wants to use 5.12 since it's the latest LTS release and we're already using it for other related projects.


  • Lifetime Qt Champion

    You may also have found a regression.

    Did you also test with a self built version of Qt 5.11 ? If not I would start by that (since you know it's working) to confirm that everything is fine and then go upward until it breaks. So you might be able to use Qt 5.12 while finding which version broke something for your device.



  • A self-built version of Qt 5.11.3 with the same configuration as my Qt 5.12.3 build works correctly with EGLFS.

    Thanks for your advice @SGaist.
    I'll figure out the first version of Qt 5.12 first experienced this and report it as a bug.



  • My previous statement is incorrect. I must have mixed up my application build directories, because my self-built version of Qt 5.11.3 is not working correctly with EGLFS.
    I apologize for the confusion.


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