topic Re: imx8 hdmi audio in Voice Technology

imx8 hdmi audio

jinmuyan — Mon, 26 Jun 2023 09:11:20 GMT

I encountered a problem in developing the voice function, in the IMX8 series development board, if you want to output audio from the HDMI port, you need to manually use the command to change the output port to HDMI, but during the development I found that all my sound card devices lack chips, in alsamixer display: This sound device does not have any controls. There is no way to adjust the volume at all, nor can you change the output device, you can only see a few sound card information, if you solve this problem so that the sound can be output normally from the HDMI port

Re: imx8 hdmi audio

giraffe508 — Mon, 26 Jun 2023 10:20:29 GMT

Hi @jinmuyan

It seems like you are having trouble with the audio output through the HDMI port on your i.MX8 development board. To resolve this issue, you can follow these steps:

First, ensure that the HDMI audio support is enabled in your kernel configuration. You can check this by looking for the following line in your kernel configuration file (usually located at arch/arm64/configs/defconfig):
```
CONFIG_SND_SOC_IMX_HDMI=y
```
If it's not present, add it and rebuild your kernel.

Next, verify that the correct device tree bindings are in place for the HDMI audio. You should have an entry similar to this in your device tree file (usually located at arch/arm64/boot/dts/freescale/):
```
hdmi_audio: hdmi_audio {     compatible = 'fsl,imx-audio-hdmi';     model = 'imx-hdmi';     status = 'okay'; };
```
If it's not present, add it and rebuild your device tree.

Once the kernel and device tree are properly configured, you should be able to see the HDMI audio device in the ALSA mixer. You can use the following command to list all available sound cards and their corresponding devices:
```
aplay -l
```
Look for a card with a description similar to 'imx-hdmi'.

To change the default audio output to the HDMI device, you can create or modify the /etc/asound.conf file with the following content (replace 'card_number' and 'device_number' with the appropriate values from the previous step):
```
pcm.!default {     type hw     card card_number     device device_number }
ctl.!default {     type hw     card card_number }
```
Save the file and restart the ALSA service.

After completing these steps, you should be able to output audio through the HDMI port on your i.MX8 development board. If you still encounter issues, please provide more information about your setup, including the specific i.MX8.

Kind Regards,

Re: imx8 hdmi audio

jinmuyan — Tue, 27 Jun 2023 01:18:17 GMT

First of all, thank you very much for your help, but I also need to elaborate on my problem, my development needs are to need to output sound separately from the HDMI, and I have an adapter, it has two outputs, a headphone jack and a VGA port, I need to plug in the headphones to let the sound go through the adapter and then through the headphones, but my problem now is that I have all the sound card equipment.I can see all sound card devices including vm8524, imx-hdmi, etc. through the aplay -l command, but in ALSAmixer I have no way to adjust the volume, prompting me to lack firmware, as shown in the image below, I suspect that it may be that my burning file is incomplete, so can you analyze what caused it or tell me where to find the official standard burning file?

Thank you very much for your help