How to judge USB Audio device has no digital in/out.

[Chengyi Zhao]

Hi guys,

I found that in the following configuration file "alsa-lib/src/conf/cards/USB-Audio.conf" there are many kinds of
USB Audio devices that need to turn off digital in/out.

However, how can I judge that this USB Audio device has no digital in/out, thanks.

USB-Audio.pcm.iec958_device {

        # The below don't have digital in/out, so prevent them from being opened.
        "Andrea PureAudio USB-SA Headset" 999
        "Blue Snowball" 999
        "C-Media USB Headphone Set" 999
        "Cmedia Audio" 999
        "DELL PROFESSIONAL SOUND BAR AE5" 999
        "HP Digital Stereo Headset" 999
        "GN 9330" 999
        "Logitech Speaker Lapdesk N700" 999
        "Logitech G35 Headset" 999
        "Logitech USB Headset" 999
        "Logitech USB Headset H540" 999
        "Logitech Wireless Headset" 999
        "Plantronics Blackwire 3220 Seri" 999
        "Plantronics GameCom 780" 999
        "Plantronics USB Headset" 999
        "Plantronics Wireless Audio" 999
        "SB WoW Headset" 999
        "Scarlett 2i2 USB" 999
        "Scarlett 2i4 USB" 999
        "Sennheiser USB headset" 999
        "SWTOR Gaming Headset by Razer" 999
        "ThinkStation P620 Main" 999
        "ThinkStation P620 Rear" 999
        "Thunderbolt Dock Audio Headset" 999
        "Thunderbolt Dock Audio Module" 999
        "USB Device 0x46d_0x821" 999
        "USB Device 0x46d_0x992" 999
        "WD15 Dock" 999
        "WD19 Dock" 999
}

Best Regards,
Chengyi