Vanfanel
Posts: 436
Joined: Sat Aug 18, 2012 5:58 pm

Is the BCM2835 module needed for vc4_hdmi audio to work?

Mon Mar 11, 2019 10:31 am

Hi there,

I have been trying to get the vc4_hdmi audio to work in my own aarch64 debian system with the latest raspberrypi kernel sources built for aarch64.
I am using the vc4 overlay (dtoverlay=vc4-kms-v3d).
aplay -l lists the vc4hdmi card as card 0, and if I set dtparam=audio=on on config.txt, the ALSA card (meaning the bcm2835 ALSA card) is also listed and of course it works fine using both hdmi and jack audio.

So, if I DON'T load the bcm2835 modules, am I supposed to get audio using vc4hdmi alone? I guess so, since it IS a card registered by the kernel that ALSA detects, but alsamixer says it has "no controls available", and no API (SDL2, libretro, etc) is able to make it sound.
I have seen that vc4hdmi audio was incorporated into the kernel back in 2017, and it IS supposed to be working by now, but I don't know if it's supposed to work without bcm2835 sound modules.

So, what am I misunderstanding here?


Thanks!

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