Tdx-reference-multimedia with Qt application QPA

Technical Support
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1

Hi,

I have tried to install a boot2qt image on my Apalis IMX8 and launched my custom Qt Qml application
I was surprised that the image was managing eglfs as Qt qpa backend.

Previously, I have isntalled the toradex-reference-multimedia image and at first glance, Wayland is the backend to use.

Could you please confirm me I’m not wrong ?

If so, is it possible to run a Qt application with eglfs with the toradex-reference-multimedia ?
I mean, is there a way to build the toradex-reference-image

with eglfs enabled ?

Thanks.

K

2

Hello @karim,

You are right that the toradex-reference-multimedia has Weston as a Backend. It will ship with booting into Wayland/Weston into a terminal window GUI, and have GStreamer functionality to test media playback and encoding/decoding.

The newer iMX8 GPUs as well as the iMX6 have a proper DRM interface. So, no special plug-in would be needed, as in this case, Qt EGLFS. The rendering engine eglfs_kms can be used (select it through QT_QPA_EGLFS_INTEGRATION).

You can find more information on this topic here: Qt for Embedded Linux | Qt 5.15

Hope it helps!

BR, Janani

3

Hi @saijanani.tx

thanks for your feedback.
Do you mean that I’d need to run a qt application using the syntax: myapp -platform eglfs_kms ?

4

Yes, right! You could check here for moe information: Qt for Embedded Linux | Qt 5.15

Best regards,
Janani

5

hi @saijanani.tx

Thanks a lot for your feedback.
I was finally able to launch a testapp with eglfs_kms…itr definitly saves my working day !

For those who are interested, also consider setting the following variables:

export QT_QPA_EGLFS_KMS_CONFIG=/opt/qmltest/bin/kms.json
export QT_QPA_EGLFS_INTEGRATION=eglfs_kms
export QT_QPA_PLATFORM=eglfs
export QT_QPA_EGLFS_ALWAYS_SET_MODE=1

The kms.json file I used for testing purposes is very basic:

{
  "device": "/dev/dri/card1",
  "hwcursor": false,
  "pbuffers": true,
  "outputs": [
    {
      "name": "VGA1",
      "mode": "off"
    },
    {
      "name": "HDMI1"
    }
  ]
}
2 Likes
6

Hello @karim ,

Thanks a lot for your feedback and also for the code snippet here. It is a valuable addition to our community. I am glad we could be of help.

Best regards,
Janani

7

You are a lifesaver ! Thank you so much for posting this !