iMX6 -- EGL: Warning: No default display support on wayland; Could not open egl display

RRO_VI

Hi,

I have upgraded the yocto release used on our iMX6 SOM from Krogoth to Dunfell, and am no longer able to use the qmlscene application with EGLFS (or any of the available platforms). The image is wayland based

Kernel Version:

5.4.85-6

QT Version:

5.14.2

Relevant QT exports:

QT_QPA_PLATFORM=eglfs
XDG_RUNTIME_DIR=/run/user/0
DISPLAY=:0.0

I have also tried

WAYLAND_DISPLAY=/dev/fb0
and/or
WAYLAND_DISPLAY=wayland-0
and
QT_QPA_EGLFS_FB=/dev/fb0

QT configuration:

Build options:
  Mode ................................... release
  Optimize release build for size ........ no
  Building shared libraries .............. yes
  Using C standard ....................... C11
  Using C++ standard ..................... C++17
  Using ccache ........................... no
  Using new DTAGS ........................ yes
  Relocatable ............................ yes
  Using precompiled headers .............. no
  Using LTCG ............................. no
  Target compiler supports:
    NEON ................................. yes
  Build parts ............................ libs tests tools
Qt modules and options:
  Qt Concurrent .......................... yes
  Qt D-Bus ............................... yes
  Qt D-Bus directly linked to libdbus .... yes
  Qt Gui ................................. yes
  Qt Network ............................. yes
  Qt Sql ................................. yes
  Qt Testlib ............................. yes
  Qt Widgets ............................. yes
  Qt Xml ................................. yes
Support enabled for:
  Using pkg-config ....................... yes
  udev ................................... yes
  Using system zlib ...................... yes
  Zstandard support ...................... no
Qt Core:
  DoubleConversion ....................... yes
    Using system DoubleConversion ........ no
  GLib ................................... no
  iconv .................................. no
  ICU .................................... no
  Built-in copy of the MIME database ..... yes
  Tracing backend ........................ <none>
  Logging backends:
    journald ............................. no
    syslog ............................... yes
    slog2 ................................ no
  PCRE2 .................................. no
    Using system PCRE2 ................... yes
Qt Network:
  getifaddrs() ........................... yes
  IPv6 ifname ............................ yes
  libproxy ............................... no
  Linux AF_NETLINK ....................... yes
  OpenSSL ................................ yes
    Qt directly linked to OpenSSL ........ no
  OpenSSL 1.1 ............................ yes
  DTLS ................................... yes
  OCSP-stapling .......................... yes
  SCTP ................................... no
  Use system proxies ..................... yes
  GSSAPI ................................. no
Qt Gui:
  Accessibility .......................... yes
  FreeType ............................... yes
    Using system FreeType ................ yes
  HarfBuzz ............................... yes
    Using system HarfBuzz ................ no
  Fontconfig ............................. yes
  Image formats:
    GIF .................................. no
    ICO .................................. no
    JPEG ................................. yes
      Using system libjpeg ............... yes
    PNG .................................. yes
      Using system libpng ................ yes
  Text formats:
    HtmlParser ........................... yes
    CssParser ............................ yes
    OdfWriter ............................ yes
    MarkdownReader ....................... yes
      Using system libmd4c ............... no
    MarkdownWriter ....................... yes
  EGL .................................... yes
  OpenVG ................................. yes
  OpenGL:
    Desktop OpenGL ....................... no
    OpenGL ES 2.0 ........................ yes
    OpenGL ES 3.0 ........................ yes
    OpenGL ES 3.1 ........................ no
    OpenGL ES 3.2 ........................ no
  Vulkan ................................. no
  Session Management ..................... no
Features used by QPA backends:
  evdev .................................. yes
  libinput ............................... yes
  INTEGRITY HID .......................... no
  mtdev .................................. no
  tslib .................................. no
  xkbcommon .............................. no
  X11 specific:
    XLib ................................. no
    XCB Xlib ............................. no
    EGL on X11 ........................... no
QPA backends:
  DirectFB ............................... no
  EGLFS .................................. yes
  EGLFS details:
    EGLFS OpenWFD ........................ no
    EGLFS i.Mx6 .......................... yes
    EGLFS i.Mx6 Wayland .................. yes
    EGLFS RCAR ........................... no
    EGLFS EGLDevice ...................... no
    EGLFS GBM ............................ no
    EGLFS VSP2 ........................... no
    EGLFS Mali ........................... no
    EGLFS Raspberry Pi ................... no
    EGLFS X11 ............................ no
  LinuxFB ................................ no
  VNC .................................... yes
Qt Sql:
  SQL item models ........................ yes
Qt Widgets:
  GTK+ ................................... no
  Styles ................................. Fusion Windows
Qt PrintSupport:
  CUPS ................................... no
Qt Sql Drivers:
  DB2 (IBM) .............................. no
  InterBase .............................. no
  MySql .................................. no
  OCI (Oracle) ........................... no
  ODBC ................................... no
  PostgreSQL ............................. no
  SQLite2 ................................ no
  SQLite ................................. no
    Using system provided SQLite ......... no
  TDS (Sybase) ........................... no
Qt Testlib:
  Tester for item models ................. yes

Installed libs:

libegl-imx - 1:6.4.0.p2.4-aarch32-r0
libgles2-imx - 1:6.4.0.p2.4-aarch32-r0
libgles2-imx - 1:6.4.0.p2.4-aarch32-r0

Kernel config contains:

CONFIG_MXC_GPU_VIV=y

Error message when starting qmlscene:

EGL: Warning: No default display support on wayland
Could not open egl display

I have read/tried everything in:
https://forum.qt.io/topic/73383/could-not-open-egl-display/2
and to the best of my knowledge, everything on any relevant "how to use qt on imx6" wiki or site I have been able to find

Thank you in advance for any help

Edit1:

One difference I have noticed in the debug output is the selected plugin:

(working) eglfs_viv
(non-working) eglfs_emu

Working:

Got keys from plugin meta data ("eglfs_viv_wl")
QFactoryLoader::QFactoryLoader() checking directory path "/usr/bin/qt5/egldeviceintegrations" ...
qt.qpa.egldeviceintegration: EGL device integration plugin keys: ("eglfs_viv", "eglfs_viv_wl")
qt.qpa.egldeviceintegration: EGL device integration plugin keys (sorted): ("eglfs_viv", "eglfs_viv_wl")
qt.qpa.egldeviceintegration: Trying to load device EGL integration "eglfs_viv"
loaded library "/usr/lib/qt5/plugins/egldeviceintegrations/libqeglfs-viv-integration.so"
qt.qpa.egldeviceintegration: Using EGL device integration "eglfs_viv"

Non-working:

Got keys from plugin meta data ("eglfs_viv_wl")
QFactoryLoader::QFactoryLoader() checking directory path "/usr/bin/egldeviceintegrations" ...
qt.qpa.egldeviceintegration: EGL device integration plugin keys: ("eglfs_emu", "eglfs_viv", "eglfs_viv_wl")
qt.qpa.egldeviceintegration: EGL device integration plugin keys (sorted): ("eglfs_emu", "eglfs_viv", "eglfs_viv_wl")
qt.qpa.egldeviceintegration: Trying to load device EGL integration "eglfs_emu"
loaded library "/usr/lib/plugins/egldeviceintegrations/libqeglfs-emu-integration.so"
qt.qpa.egldeviceintegration: Using EGL device integration "eglfs_emu"
EGL: Warning: No default display support on wayland
Could not open egl display
Aborted

Edit2:

It seems I have answered/solved (part) of my own question.

removing the libqeglfs-emu-integration.so shared library fixes the issue, as now only libqeglfs-viv-integration.so is found and used. Why this was/is an issue? I am not yet sure.

Edit3:

export QT_QPA_EGLFS_INTEGRATION=eglfs_viv

fixes the issue