cm108

dmesg:
[962951.850375] usb 1-1: new full-speed USB device number 89 using xhci_hcd
[962951.991336] usb 1-1: New USB device found, idVendor=0d8c, idProduct=000c, bcdDevice= 1.00
[962951.991351] usb 1-1: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[962951.991358] usb 1-1: Product: C-Media USB Headphone Set
[962952.005356] input: C-Media USB Headphone Set   as /devices/pci0000:00/0000:00:14.0/usb1/1-1/1-1:1.3/0003:0D8C:000C.000F/input/input43
[962952.060355] hid-generic 0003:0D8C:000C.000F: input,hidraw1: USB HID v1.00 Device [C-Media USB Headphone Set  ] on usb-0000:00:14.0-1/input3

aplay -l:
[user Downloads]$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: ALC295 Analog [ALC295 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 7: HDMI 1 [HDMI 1]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 8: HDMI 2 [HDMI 2]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 9: HDMI 3 [HDMI 3]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 10: HDMI 4 [HDMI 4]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: Set [C-Media USB Headphone Set], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0



aplay -L:
[user Downloads]$ aplay -L
null
    Discard all samples (playback) or generate zero samples (capture)
lavrate
    Rate Converter Plugin Using Libav/FFmpeg Library
samplerate
    Rate Converter Plugin Using Samplerate Library
speexrate
    Rate Converter Plugin Using Speex Resampler
jack
    JACK Audio Connection Kit
oss
    Open Sound System
pipewire
    PipeWire Sound Server
pulse
    PulseAudio Sound Server
speex
    Plugin using Speex DSP (resample, agc, denoise, echo, dereverb)
upmix
    Plugin for channel upmix (4,6,8)
vdownmix
    Plugin for channel downmix (stereo) with a simple spacialization
sysdefault:CARD=PCH
    HDA Intel PCH, ALC295 Analog
    Default Audio Device
front:CARD=PCH,DEV=0
    HDA Intel PCH, ALC295 Analog
    Front output / input
surround21:CARD=PCH,DEV=0
    HDA Intel PCH, ALC295 Analog
    2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=PCH,DEV=0
    HDA Intel PCH, ALC295 Analog
    4.0 Surround output to Front and Rear speakers
surround41:CARD=PCH,DEV=0
    HDA Intel PCH, ALC295 Analog
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=PCH,DEV=0
    HDA Intel PCH, ALC295 Analog
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=PCH,DEV=0
    HDA Intel PCH, ALC295 Analog
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=PCH,DEV=0
    HDA Intel PCH, ALC295 Analog
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
hdmi:CARD=PCH,DEV=0
    HDA Intel PCH, HDMI 0
    HDMI Audio Output
hdmi:CARD=PCH,DEV=1
    HDA Intel PCH, HDMI 1
    HDMI Audio Output
hdmi:CARD=PCH,DEV=2
    HDA Intel PCH, HDMI 2
    HDMI Audio Output
hdmi:CARD=PCH,DEV=3
    HDA Intel PCH, HDMI 3
    HDMI Audio Output
hdmi:CARD=PCH,DEV=4
    HDA Intel PCH, HDMI 4
    HDMI Audio Output
usbstream:CARD=PCH
    HDA Intel PCH
    USB Stream Output
sysdefault:CARD=Set
    C-Media USB Headphone Set, USB Audio
    Default Audio Device
front:CARD=Set,DEV=0
    C-Media USB Headphone Set, USB Audio
    Front output / input
surround21:CARD=Set,DEV=0
    C-Media USB Headphone Set, USB Audio
    2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=Set,DEV=0
    C-Media USB Headphone Set, USB Audio
    4.0 Surround output to Front and Rear speakers
surround41:CARD=Set,DEV=0
    C-Media USB Headphone Set, USB Audio
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Set,DEV=0
    C-Media USB Headphone Set, USB Audio
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Set,DEV=0
    C-Media USB Headphone Set, USB Audio
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Set,DEV=0
    C-Media USB Headphone Set, USB Audio
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=Set,DEV=0
    C-Media USB Headphone Set, USB Audio
    IEC958 (S/PDIF) Digital Audio Output
usbstream:CARD=Set
    C-Media USB Headphone Set
    USB Stream Output



[user Downloads]$ amixer -c 1 controls
numid=5,iface=MIXER,name='Headphone Playback Switch'
numid=6,iface=MIXER,name='Headphone Playback Volume'
numid=3,iface=MIXER,name='Mic Playback Switch'
numid=4,iface=MIXER,name='Mic Playback Volume'
numid=7,iface=MIXER,name='Mic Capture Switch'
numid=8,iface=MIXER,name='Mic Capture Volume'
numid=9,iface=MIXER,name='Auto Gain Control'
numid=2,iface=PCM,name='Capture Channel Map'
numid=1,iface=PCM,name='Playback Channel Map'

Note: missing any iec958-related switch, e.g. "IEC958 Output Switch".


amixer cget:
[user Downloads]$  amixer -c 1 cget iface=PCM,name='Playback Channel Map'
numid=1,iface=PCM,name='Playback Channel Map'
  ; type=INTEGER,access=r----R--,values=2,min=0,max=36,step=0
  : values=0,0
  | container
    | chmap-fixed=FL,FR



amixer cset:
[user Downloads]$ amixer -c 1 cset iface=PCM,name='Playback Channel Map' 3,4
amixer: Control sysdefault:1 element write error: Operation not permitted


sudo strace speaker-test -D iec958:Set -c2 2>&1
[...]
openat(AT_FDCWD, "/dev/snd/pcmC1D999p"