mjhjmtu

I use the (great) AK5370 microphone for Skype, but it is not recognized by my archlinux i86_64.
It also fails to recognize the mic on my Logitech Webcam (PTZ, which I do not use).

Both are connected through the monitor's built-in hub, and both work through hubs an another system. Both work on the same hardware with Ubuntu and Windows.

Here they are on lsusb…

 ~]# lsusb
Bus 001 Device 002: ID 03f0:2524 Hewlett-Packard LP3065 30" Monitor Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 003: ID 1532:001c Razer USA, Ltd RZ01-0036 Optical Gaming Mouse [Abyssus]
Bus 001 Device 004: ID 04ca:002a Lite-On Technology Corp. 
Bus 001 Device 005: ID 0556:0001 Asahi Kasei Microsystems Co., Ltd AK5370 I/F A/D Converter
Bus 001 Device 006: ID 046d:08cc Logitech, Inc. Mic (PTZ)

But not on aplay's list-devices...

]$ aplay --list-devices
**** List of PLAYBACK Hardware Devices ****
card 0: NVidia [HDA NVidia], device 0: ALC1200 Analog [ALC1200 Analog]
 Subdevices: 0/1
 Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 3: ALC1200 Digital [ALC1200 Digital]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 1: NVidia_1 [HDA NVidia], device 3: HDMI 0 [HDMI 0]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 1: NVidia_1 [HDA NVidia], device 7: HDMI 0 [HDMI 0]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 1: NVidia_1 [HDA NVidia], device 8: HDMI 0 [HDMI 0]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 1: NVidia_1 [HDA NVidia], device 9: HDMI 0 [HDMI 0]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 2: NVidia_2 [HDA NVidia], device 3: HDMI 0 [HDMI 0]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 2: NVidia_2 [HDA NVidia], device 7: HDMI 0 [HDMI 0]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 2: NVidia_2 [HDA NVidia], device 8: HDMI 0 [HDMI 0]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 2: NVidia_2 [HDA NVidia], device 9: HDMI 0 [HDMI 0]
 Subdevices: 1/1

note: card0 mobo card1&2 nvidia graphics (not used)

PulseAudio Volume Control reports "No input device available".

No problem with these devices on other systems

Alas...

pulseaudio 3.0-3
pavucontrol 2.0-1
skype 4.2.0.11-1
alsa-lib 1.0.27.1-1

Note: the webcam (UVC) with the min (PTZ) is recognized and works.

Per Ignacio Vazquez-Abrams... (thanks)

~]$ lsmod | grep '^snd' | column -t
snd_usb_audio 112569 0
snd_usbmidi_lib 18931 1 snd_usb_audio
snd_rawmidi 18742 1 snd_usbmidi_lib
snd_seq_device 5180 1 snd_rawmidi
snd_hda_codec_hdmi 29298 8
snd_hda_codec_realtek 30893 1
snd_hda_intel 35816 4
snd_hda_codec 145704 3 snd_hda_codec_realtek,snd_hda_codec_hdmi,snd_hda_intel
snd_hwdep 6364 2 snd_usb_audio,snd_hda_codec
snd_pcm 76860 4 snd_usb_audio,snd_hda_codec_hdmi,snd_hda_codec,snd_hda_intel
snd_page_alloc 7330 2 snd_pcm,snd_hda_intel
snd_timer 18687 1 snd_pcm
snd 58893 19 snd_hda_codec_realtek,snd_usb_audio,snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_pcm,snd_rawmidi,snd_usbmidi_lib,snd_hda_codec,snd_hda_intel,snd_seq_device

And in addition...

]# ls -l /dev/snd
total 0
drwxr-xr-x 2 root root 100 May 24 10:07 by-path
crw-rw----+ 1 root audio 116, 8 May 24 10:07 controlC0
crw-rw----+ 1 root audio 116, 17 May 24 10:07 controlC1
crw-rw----+ 1 root audio 116, 26 May 24 10:07 controlC2
crw-rw----+ 1 root audio 116, 7 May 24 10:07 hwC0D0
crw-rw----+ 1 root audio 116, 16 May 24 10:07 hwC1D0
crw-rw----+ 1 root audio 116, 15 May 24 10:07 hwC1D1
crw-rw----+ 1 root audio 116, 14 May 24 10:07 hwC1D2
crw-rw----+ 1 root audio 116, 13 May 24 10:07 hwC1D3
crw-rw----+ 1 root audio 116, 25 May 24 10:07 hwC2D0
crw-rw----+ 1 root audio 116, 24 May 24 10:07 hwC2D1
crw-rw----+ 1 root audio 116, 23 May 24 10:07 hwC2D2
crw-rw----+ 1 root audio 116, 22 May 24 10:07 hwC2D3
crw-rw----+ 1 root audio 116, 6 May 24 10:07 pcmC0D0c
crw-rw----+ 1 root audio 116, 5 May 24 14:51 pcmC0D0p
crw-rw----+ 1 root audio 116, 2 May 24 10:07 pcmC0D2c
crw-rw----+ 1 root audio 116, 4 May 24 10:07 pcmC0D3c
crw-rw----+ 1 root audio 116, 3 May 24 10:07 pcmC0D3p
crw-rw----+ 1 root audio 116, 12 May 24 10:07 pcmC1D3p
crw-rw----+ 1 root audio 116, 11 May 24 10:07 pcmC1D7p
crw-rw----+ 1 root audio 116, 10 May 24 10:07 pcmC1D8p
crw-rw----+ 1 root audio 116, 9 May 24 10:07 pcmC1D9p
crw-rw----+ 1 root audio 116, 21 May 24 10:07 pcmC2D3p
crw-rw----+ 1 root audio 116, 20 May 24 10:07 pcmC2D7p
crw-rw----+ 1 root audio 116, 19 May 24 10:07 pcmC2D8p
crw-rw----+ 1 root audio 116, 18 May 24 10:07 pcmC2D9p
crw-rw---- 1 root audio 116, 1 May 24 10:06 seq
crw-rw----+ 1 root audio 116, 33 May 24 10:07 timer

Verify that the snd-usb-audio kernel module is available and loaded, so that ALSA can see the devices.