[AudioI] count of capture channels DIFFER ARY between hardware-SPEC and CODING in raspberrypi/linux-driver "audioinjector-addons"

[Matt Flax]

Thanks for opening this discussion Frank,

 

Indeed the board inputs 6 channels but the Linux driver reports 8.

 

The reason for this is that the cs42448 codec outputs 8 channels with two of them being silent. So physically on the I2S bus there are 8 channels output by the audio codec, however 2 of those channels are silent !

 

This it turns out is a good thing. It allows us to realign channels based on the location of the two silent channels on the input. If for whatever reason there are overruns or underruns or something else happens, then our code can always make sure the channel alignment is correct.

 

Matt
 

 
On 21/10/21 1:38 am, Frank Haferkorn via People wrote:
 
 
 

Hello at all,

 

Hallo Matt Flax ,

 

 

 

Have you seen my request https://github.com/Audio-Injector/Octo/issues/50 <https://github.com/Audio-Injector/Octo/issues/50> ?

 

 

 

“faulty settings of count of capture-channels (=8) in raspberrypi/linux/sound/soc/bcm/audioinjector-octo-soundcard.c”

 

 

 

I am not completely sure, 

 

but it seems that for the driver  audioinjector-addons of the repo: raspberrypi/linux 

 

 

 

the count of capture-channels in the spec (==6) and in the code  (==8)

 

 

 

do NOT match.

 

Maybe I am wrong? 

 

Yours,

 

               Frank Haferkorn

 

P.S.: Is this a problem for configuration detection of capture channel-count.

 

e.g. at the moment I cannot configure 6 capture channels in ALSAs /etc/asound.config

 

 

 

 

 

 

 
 
 




 

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