[alsa-devel] possible bug: input and output devices are getting mixed up

Raymond Jennings shentino at gmail.com
Mon Apr 16 03:22:56 CEST 2018


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


More information about the Alsa-devel mailing list