Garbage returned while reading unused S/PDIF, A CM106 like sound card

Garbage returned while reading unused S/PDIF, A CM106 like sound card

[Aurélien]

Hello, 

I encounter troubles while using S/PDIF input on an CM106 like sound card 
(vendor 0x0d8c, device 0x0102) when the remote device which is connected by S/
PDIF to the sound card is powered off.
In that case garbage data are reading from the S/PDIF rather than.. nothing

It is really boring since this S/PDIF input is connected to the output 
speakers and once the remote deviced is powered off it emits a really 
disturbing sound.
Since there is no input on the S/PDIF I guess that it could be a driver bug?
If it's an hardware bug (I don't encounter the problem under windows..) is it 
possible to make a hack in order to distinguish between real data and noise on 
the S/PDIF input?

Unfortunately this test is performed on an embedded device which runs linux 
5.16.17-sun50iw6. I don't know if this problem still occurs with newer alsa 
version.

Thank you in advance for your help.
Regards, 

Aurélien

Re: Garbage returned while reading unused S/PDIF, A CM106 like sound card

[Geraldo Nascimento]

On Tue, Jul 04, 2023 at 08:06:04PM +0200, Aurélien wrote:
> Hello,

Hi Aurélien!

> 
> I encounter troubles while using S/PDIF input on an CM106 like sound card 
> (vendor 0x0d8c, device 0x0102) when the remote device which is connected by S/
> PDIF to the sound card is powered off.
> In that case garbage data are reading from the S/PDIF rather than.. nothing
> 
> It is really boring since this S/PDIF input is connected to the output 
> speakers and once the remote deviced is powered off it emits a really 
> disturbing sound.
> Since there is no input on the S/PDIF I guess that it could be a driver bug?
> If it's an hardware bug (I don't encounter the problem under windows..) is it 
> possible to make a hack in order to distinguish between real data and noise on 
> the S/PDIF input?
> 
> Unfortunately this test is performed on an embedded device which runs linux 
> 5.16.17-sun50iw6. I don't know if this problem still occurs with newer alsa 
> version.

This looks like a vendor (downstream) kernel. ALSA Project does not
accept bug reports for vendor kernels. You must try to reproduce your
issue with the latest mainline kernel.

Thanks,
Geraldo Nascimento

> 
> Thank you in advance for your help.
> Regards, 
> 
> Aurélien
> 
>