I used arecord -L to list some things, and I got weird results, saying among other things that my webcam was capable of surround sound output even though it's strictly an input device.
I already reported it downstream with my distro but so far no news.
I was told it was a bug with alsa.
As for the card in question, U0x46d0x825 is my logitech brand webcam connected via USB.
$ arecord -L
null Discard all samples (playback) or generate zero samples (capture) pulse PulseAudio Sound Server sysdefault:CARD=PCH HDA Intel PCH, ALC887-VD Analog Default Audio Device front:CARD=PCH,DEV=0 HDA Intel PCH, ALC887-VD Analog Front speakers sysdefault:CARD=U0x46d0x825 USB Device 0x46d:0x825, USB Audio Default Audio Device front:CARD=U0x46d0x825,DEV=0 USB Device 0x46d:0x825, USB Audio Front speakers surround21:CARD=U0x46d0x825,DEV=0 USB Device 0x46d:0x825, USB Audio 2.1 Surround output to Front and Subwoofer speakers surround40:CARD=U0x46d0x825,DEV=0 USB Device 0x46d:0x825, USB Audio 4.0 Surround output to Front and Rear speakers surround41:CARD=U0x46d0x825,DEV=0 USB Device 0x46d:0x825, USB Audio 4.1 Surround output to Front, Rear and Subwoofer speakers surround50:CARD=U0x46d0x825,DEV=0 USB Device 0x46d:0x825, USB Audio 5.0 Surround output to Front, Center and Rear speakers surround51:CARD=U0x46d0x825,DEV=0 USB Device 0x46d:0x825, USB Audio 5.1 Surround output to Front, Center, Rear and Subwoofer speakers surround71:CARD=U0x46d0x825,DEV=0 USB Device 0x46d:0x825, USB Audio 7.1 Surround output to Front, Center, Side, Rear and Woofer speakers iec958:CARD=U0x46d0x825,DEV=0 USB Device 0x46d:0x825, USB Audio IEC958 (S/PDIF) Digital Audio Output