[alsa-devel] Control vs Device

Jean-Yves Avenard jyavenard at gmail.com
Tue Apr 27 08:47:20 CEST 2010


Currently maintaining the audio code on the MythTV project...

Lately, I've had reports on issues by users when using digital audio.

This for some reasons however fails, unless the device opened is
something like : IEC958:{AES0: 0x06}

When we are about to configure a digital audio stream, we do the
equivalent of what iecset does. So I would have thought that our code
should work under most circumstances...

Then I started to suspect the code setting the IEC958_AES0_NONAUDIO bit.

We always open the "default" controller like so:
snd_ctl_open(&ctl, "default", 0)

I thought that maybe the issue is that the "default" controller isn't
the one to open.

Is there a way, from the name of the device card ; to retrieve which
controller is used?

So before opening a specific ALSA audio device, I find the
corresponding controller, set the flag non-audio on it and continue as

I couldn't find any functions nor documentation that would help me
achieve such results..

Any hints would be greatly appreciated...

Thank you !!

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