Inquiry Regarding Audio Output via HDMI using NXP/Freescale i.MX 8M Mini Module with Dahlia Carrier Board

I am reaching out to inquire about the possibility of configuring audio output via HDMI using the NXP/Freescale i.MX 8M Mini module in conjunction with the Dahlia carrier board.

I have been exploring the resources available on your website, particularly the section on audio configuration in Linux (Audio (Linux) | Toradex Developer Center). However, I couldn’t find specific information on enabling HDMI audio output.

Could you please provide guidance or documentation on how to achieve HDMI audio output using these modules and the Dahlia board? Any insights or references you can offer would be greatly appreciated.

Thank you very much for your assistance. I look forward to hearing from you soon.

Best regards,
Ferran

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Hello Ferran,

The NXP/Freescale i.MX 8M Mini and Plus modules support HDMI audio output, but the capability to utilize this feature also depends on the carrier board and the software configuration. Since you are using the Dahlia carrier board, it’s important to note that while the Dahlia board supports various interfaces, the direct support for HDMI audio output would primarily depend on the module’s capabilities and the software setup.

For the i.MX 8M Mini/Plus modules with the Dahlia carrier board, you should ensure that your software configuration is correctly set up to route audio over HDMI. This involves configuring the device tree and making sure the Linux kernel is compiled with support for HDMI audio for the i.MX 8M Mini/Plus SoC. Additionally, you’ll need to ensure that the ALSA (Advanced Linux Sound Architecture) configuration is set to use the HDMI audio output.

Here’s a general approach to enable HDMI audio output:

  1. Device Tree Configuration: Ensure that the HDMI audio node is enabled in the device tree specific to your module and carrier board. This might involve enabling the HDMI audio interface and specifying the correct audio codec.

  2. Kernel Configuration: Verify that your Linux kernel is compiled with support for the i.MX 8M Mini/Plus HDMI audio. This typically involves enabling the necessary drivers in the kernel configuration (make menuconfig).

  3. ALSA Configuration: Use the alsamixer or amixer tool to ensure that the HDMI audio output is not muted and is selected as the default audio output device. You might need to adjust the .asoundrc file or use the amixer tool to set the HDMI interface as the default audio device.

  4. GStreamer Configuration: If you are using GStreamer for audio playback, ensure that your pipeline is configured to use the correct ALSA device for HDMI audio output. This can be specified in the GStreamer pipeline using the alsasink element.

  5. Testing: You can test HDMI audio output using the aplay command or any other audio playback tool that supports ALSA. Be sure to select the correct audio device corresponding to the HDMI output.

Please note that specific steps might vary based on the exact version of the Linux kernel and the software stack you are using. If you encounter any issues, checking the kernel and system logs (dmesg and journalctl) can provide insights into any configuration or hardware detection issues.

Best regards,
Torad

Please, also check if these links can help you solve your problem:

Audio (Linux) | Toradex Developer Center.

Hello @ferranmc,

The hardware of the Verdin DSI to HDMI converter is capable of transmitting audio via HDMI, however, the current software configuration is not setup for that.

We will look into what would be necessary to enable such use case.
When we have further updates, I will send them on this thread.

Best Regards,
Bruno

Hello @ferranmc,

As for the Toradex BSP 6, the driver for the LT8912B DSI to HDMI bridge which is present on the Verdin DSI to HDMI adapter does not support the HDMI audio feature.
This is the reason why this feature is not currently enabled.

Therefore, to enable this feature some driver development is needed.

Is this required for your project?

Best Regards,
Bruno

Hi Bruno,

Yes, we need HDMI for our project. Could you please provide us with the steps to use that development driver?

Thank you very much.

Best regards,
Ferran

Hello @ferranmc,

Thanks for clarifying that this is a requirement for your project.

In my previous post I meant that driver development is needed to add this functionality to the existing driver.
We are not aware of an existing driver for the LT8912B which supports audio via HDMI.

As an alternative, HDMI audio is available and supported on the native HDMI interface on the Verdin iMX8M Plus.

Best Regards,
Bruno