Hi @jsulm
Thanks for you response :-)

I think i have setup the sysroot correctly. In the "Preferences" -> "Kits" and under the Sysroot, i have defined:
/opt/fsl-imx-wayland/6.6-scarthgap-imx-full-image/sysroots/cortexa7t2hf-neon-poky-linux-gnueabi

There is nothing general in the docs, that would say: This is faster, because….
Qt 6 follows a general trend: Use more caching for the sake of speed. There were some optimisations in container classes and string views. We fixed a mem leak in the Quick pixmap cache.

The downside of more caching, in other words higher memory consumption, is that older memory constrained setups (mainly embedded) need to swap out and actually become slower.

But I guess that’s not a Qt specific phenomenon. All frameworks and other tools I use on a daily basis, have increased their appetite for memory as RAM becomes cheaper and larger.

@mj01 Up to you to use or not to use debugger to get more information about your issue, I'm out...

@Medievil As far as i know dunfell is the most stable branch.i used yocto from dunfell and meta-qt5 from dunfell.I did not make any modification to package configurations.Everything is working fine

@AROH 1.16.1 is pretty old and has more memory leaks if vaapi for intel card is applied.
I am using gstreamer 1.22.5 + Qt 5.15.2 in Ubuntu 22.04.
However, your problem may be related to missing lib or plugins. Set GST_DEBUG level to see what is wrong.
https://gstreamer.freedesktop.org/documentation/tutorials/basic/debugging-tools.html?gi-language=c

@drebelpai the reason is that 6.5 will only enter the LTS phase after 6.5.3 is
out.

That is, for the first patch level releases, any LTS release is just a normal release, with both open source and commercial sources being available. But after Qt 6.6.0 is released, Qt 6.5 normally wouldn't get any scheduled updates anymore. This is where the commercial-only LTS releases come into play.

You also notice that in the screenshot: There's a lts-6.2.5 branch, but no lts-6.2.4 branch. This is because Qt 6.2.4 was still a non-lts patch level release (see also https://wiki.qt.io/Qt_6.2_Release).

Anyhow, I agree that the terminology here is confusing.

@Bjorn-Gurnett You have to configure it in metaqt receipe

@jsulm I wasn't aware it was not released yet. Back to building Yocto for Qt 5.15.2 then. Thanks!

Sorry folks, the question was vague and the begining of a development...
Apparently to make Qt Quick Scene Graph work on an embedded system displaying GUI on the frame buffer, we need to recompile Qt on Yocto, and provide fake/dummy libraries ligEGL.so and libGLES.so
Obviously it will be rendered using software, as there is no hardware graphic support in that case, but it still needs "empty" libGLES.so to do so.
...

Sorry to reopen the ticket. But I think we can add an answer for whoever ends up here in the future.

I have the same issue, also had libxkbcommon into the image under /usr/lib/ and kept having the same error.

The problem was basically on Yocto build I missed configuring the qtbase PACKAGECONFIG variable to enable the xkbcommon option.

To do that, you add a new layer, create a qtbase_%.bbappend file and add:

PACKAGECONFIG:append:<machinename> = " xkbcommon"

NOTE: If you don't add the <machinename> you will have failures because other packages won't have the -native extension.
NOTE2: make sure to do that in a clean build (or clean all qt packages), other ptest will fail complaining that a configuration was changed and it doesn't know why.

Hi,

Well, if your target sysroot does not provide X11, then the xcb backend won't work. Either add X11 to your target or select a more appropriate backend like EGLFS, LinuxFB, wayland, etc.

@SGaist I don't think so but in the meantime I don't see any package which could do it. My board support OpenGl ES2 so I tried some stuff like adding "PACKAGE CONFIG += "gles2" " to my qtbase bb file but nothing has changed ...

Also tried to add PACKAGECONFIG_append_pn-qtbase = "gles2" in my local.conf but no change.

After some googling, I found that the error was printed by this code : https://code.qt.io/cgit/qt/qtbase.git/tree/src/plugins/platforms/xcb/qxcbbackingstore.cpp?h=dev (line 371)

Edit: Closing this issue, it was a problem of platform (by default it was using x11 which is not the one used by my embedded device) . Thanks a lot for your help again !

This is the output when I build from command line with qmake/make :

root@debian:~# echo $QMAKESPEC root@debian:~# source /opt/qtsdk-Guinault-2020.03/environment-setup-armv7at2hf-neon-linux-gnueabi root@debian:~# echo $QMAKESPEC /opt/qtsdk-Guinault-2020.03/sysroots/armv7at2hf-neon-linux-gnueabi/usr/lib/mkspecs/linux-oe-g++ root@debian:~# mkdir hellowolrd_qt root@debian:~# cd hellowolrd_qt/ root@debian:~/hellowolrd_qt# nano helloworld.cpp root@debian:~/hellowolrd_qt# nano helloworld.pro root@debian:~/hellowolrd_qt# qmake helloworld.pro Info: creating stash file /root/hellowolrd_qt/.qmake.stash root@debian:~/hellowolrd_qt# make arm-linux-gnueabihf-g++ -march=armv7-a -mthumb -mfpu=neon -mfloat-abi=hard --sysroot=/opt/qtsdk-Guinault-2020.03/sysroots/armv7at2hf-neon-linux-gnueabi -c -pipe -isystem/home/guinault/gcc-arm-8.3-2019.03-x86_64-arm-linux-gnueabihf/arm-linux-gnueabihf/include -O2 -pipe -g -feliminate-unused-debug-types --sysroot=/opt/qtsdk-Guinault-2020.03/sysroots/armv7at2hf-neon-linux-gnueabi -O2 -Wall -W -D_REENTRANT -fPIC -DQT_NO_DEBUG -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_CORE_LIB -I. -I/opt/qtsdk-Guinault-2020.03/sysroots/armv7at2hf-neon-linux-gnueabi/usr/include/QtWidgets -I/opt/qtsdk-Guinault-2020.03/sysroots/armv7at2hf-neon-linux-gnueabi/usr/include/QtGui -I/opt/qtsdk-Guinault-2020.03/sysroots/armv7at2hf-neon-linux-gnueabi/usr/include/QtCore -I. -I/opt/qtsdk-Guinault-2020.03/sysroots/armv7at2hf-neon-linux-gnueabi/usr/lib/mkspecs/linux-oe-g++ -o helloworld.o helloworld.cpp In file included from /opt/qtsdk-Guinault-2020.03/sysroots/armv7at2hf-neon-linux-gnueabi/usr/include/QtGui/qtguiglobal.h:43, from /opt/qtsdk-Guinault-2020.03/sysroots/armv7at2hf-neon-linux-gnueabi/usr/include/QtWidgets/qtwidgetsglobal.h:43, from /opt/qtsdk-Guinault-2020.03/sysroots/armv7at2hf-neon-linux-gnueabi/usr/include/QtWidgets/qapplication.h:43, from /opt/qtsdk-Guinault-2020.03/sysroots/armv7at2hf-neon-linux-gnueabi/usr/include/QtWidgets/QApplication:1, from helloworld.cpp:1: /opt/qtsdk-Guinault-2020.03/sysroots/armv7at2hf-neon-linux-gnueabi/usr/include/QtCore/qglobal.h:45:12: fatal error: type_traits: No such file or directory # include <type_traits> ^~~~~~~~~~~~~ compilation terminated. Makefile:547: recipe for target 'helloworld.o' failed make: *** [helloworld.o] Error 1 root@debian:~/hellowolrd_qt#

And this is CXX and CXXFLAGS :

root@debian:~/hellowolrd_qt# . /opt/qtsdk-Guinault-2020.03/environment-setup-armv7at2hf-neon-linux-gnueabi root@debian:~/hellowolrd_qt# echo $CXX arm-linux-gnueabihf-g++ -march=armv7-a -mthumb -mfpu=neon -mfloat-abi=hard --sysroot=/opt/qtsdk-Guinault-2020.03/sysroots/armv7at2hf-neon-linux-gnueabi root@debian:~/hellowolrd_qt# echo $CXXFLAGS -isystem/home/guinault/gcc-arm-8.3-2019.03-x86_64-arm-linux-gnueabihf/arm-linux-gnueabihf/include -O2 -pipe -g -feliminate-unused-debug-types

Anyone can help me please ?

Thank you

Sébastien