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QT5 on IMX6q - graphics stuttering after HDMI reconnect

  • Hi,

    we have an embedded QT5 application running on an IMX6 quad system. The OS is Yocto sumo (kernel 4.9.67) and the QT app is running fullscreen on eglfs at 1920x1080@30Hz on a HDMI-connected monitor.

    Everything is fine after the application starts but when the HDMI cable is dis- and reconnected or we reset the resolution at runtime via writing to /sys/class/graphics/fb0/mode the application starts dropping frames (Animations that ran smooth before start stuttering). The problem goes away when the QT application is restarted.

    What we tried until now without success:

    • Enabling HDMI at boot through the video parameter of the kernel command line
    • Upgrading Yocto to warrior

    Do you have any hints on what might cause this and what we cound try next? We're OK with patching kernel or QT code.

  • Moderators

    hi @rickp and welcome,

    I don't think this is an issue that many user's have encountered.
    So I would suggest to bring this on the mailing list of Qt.

    You may have more luck there.

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