Display-subsystemを分割して複数のframe bufferを生成したい

Technical Support
1

verdin i.mx8MPlusでHDMIとMIPI DSIで2つの映像出力を実現しようとしています。
デバイスツリーでdisplay-subsystemをhdmiとmipi-dsiで分けて作成することで別々のframe bufferが生成されました。
mipi-dsiをfb0、hdmiをfb1としたいが、hdmiがfb0、mipi-dsiがfb1となります。
Torizon 6.6.0を使用していますが、どのようにすれば実現かのうでしょうか？

2

Hi, I’m the Toradex AI Assistant. I’m in early beta, and I would appreciate your feedback.
The Toradex Support team will follow up with you shortly!

Did you like my answer?

:+1: :-1:

:handshake:

To achieve the desired framebuffer assignment on the Verdin i.MX8M Plus with Torizon 6.6.0, you will need to modify the device tree and potentially the kernel command line parameters to ensure the correct framebuffer assignment.

Here are the steps you can follow:

  1. Device Tree Modification:

    • Ensure that the device tree nodes for HDMI and MIPI DSI are correctly defined and separated.
    • You may need to adjust the aliases section in the device tree to specify the order of the framebuffers. For example:
      / {
    aliases {
        fb0 = &mipi_dsi;
        fb1 = &hdmi;
    };
};

  2. Kernel Command Line Parameters:

    • You can specify the framebuffer order using the video parameter in the kernel command line. This can be done in the U-Boot environment. For example:
      setenv vidargs 'video=DSI-1:800x480@60 video=HDMI-A-1:1920x1080@60'
saveenv

  3. U-Boot Environment:

    • Ensure that the U-Boot environment variables are set correctly to pass the desired framebuffer configuration to the kernel. You can do this by modifying the vidargs variable as shown above.

  4. Weston Configuration:

    • If you are using Weston as your compositor, ensure that the weston.ini file is configured correctly to handle the framebuffers. You can specify the outputs in the weston.ini file located at /etc/xdg/weston/weston.ini:
      [output]
name=DSI-1
mode=800x480@60

[output]
name=HDMI-A-1
mode=1920x1080@60

By following these steps, you should be able to assign fb0 to MIPI DSI and fb1 to HDMI on your Verdin i.MX8M Plus module running Torizon 6.6.0.

Best regards, Toradex AI Assistant

3

Dear @pal_mouri , never tested this but I think answer 1 from @ToradexAI is the way to go.

Have you tried to use the alias in your display-subsystem device tree overlay?

4

@pal_mouri 進捗はいかがでしょうか。もし追加のサポートが必要になりましたら、お気軽にご連絡ください。