[alsa-devel] [PATCH] USB-Audio: Disable "Logitech USB Headset" iec958 device

[Raymond Yau]

2012/3/7, David Henningsson <david.henningsson at canonical.com>:
> Because Logitech USB Headsets do not have any digital devices,
> prevent them from being opened. This simplifies probing the
> device in PulseAudio.
>
> BugLink: https://bugs.launchpad.net/bugs/940145
> Signed-off-by: David Henningsson <david.henningsson at canonical.com>
> ---
>
> I did not get any responses to my "digital profile" mail sent to alsa-devel
> Feb 24th, but it seems the easiest workaround is the below patch for
> alsa-lib.
> Alsa-info at:
> https://bugs.launchpad.net/ubuntu/+source/pulseaudio/+bug/940145/+attachment/2778111/+files/alsa-info.txt.xWdouSRV4Z
>
>  src/conf/cards/USB-Audio.conf |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/src/conf/cards/USB-Audio.conf b/src/conf/cards/USB-Audio.conf
> index 0726c34..f488284 100644
> --- a/src/conf/cards/USB-Audio.conf
> +++ b/src/conf/cards/USB-Audio.conf
> @@ -36,6 +36,8 @@ USB-Audio.pcm.surround40_type {
>  # number for the iec958 device can be changed here.
>  USB-Audio.pcm.iec958_device {
>  	# "NoiseBlaster 3000" 42
> +	# Make sure we can't open this device digitally, because it does not exist
> +	"Logitech USB Headset" 999
>  }
>
>

your patch does not fix the "IEC958" at device 0 for "Logitech Web Camera"

arecord -L

iec958:CARD=U0x46d0x992,DEV=0
    USB Device 0x46d:0x992, USB Audio
    IEC958 (S/PDIF) Digital Audio Output