[pulseaudio-discuss] Why does the USB headset show the Digital Output (S/PDIF) port?

[Tanu Kaskinen]

On Tue, 2022-06-28 at 15:21 +0800, zhaochengyi at uniontech.com wrote:
> Hi guys,
> 
> I have a USB headset that the module is Edifier USB K800.
> Plug it into the PC's usb port, and then I found "Digital Output 
> (S/PDIF)" audio port as below.
> 
> Would you please tell me why the Digital Output (S/PDIF) port has been 
> shown, and how to verify if this USB headset really have the output 
> function of Digital Output (S/PDIF), and how to close this audio port.
> 
> Thanks a lot!

Many USB sound cards show non-existent S/PDIF devices, probably because
the default configuration in ALSA maps both analog and digital to
device 0. It's possible to disable the S/PDIF output in
/usr/share/alsa/cards/USB-Audio.conf, see the section starting with

    USB-Audio.pcm.iec958_device {

There you can add your sound card's name, the only problem is that I
haven't figured out what name should be used. Some ideas to try (the
999 part makes the device number for S/PDIF to be 999, which does not
work and therefore PulseAudio will stop showing the S/PDIF output):

    "USB PnP Sound Device" 999
    "C-Media Electronics Inc. USB PnP Sound Device" 999
    "Edifier USB K800" 999

Restart PulseAudio to test your changes.

-- Tanu