Re: A persistent name for a sound device.

[Alan Greenberger <alanjg@ptd.net>]

On 2014-02-03, peter@easthope.ca <peter@easthope.ca> wrote:
> I'm interested to make a persistent name for a sound device. 
> The output of "udevadm info -a -p $(udevadm info -q path -n /dev/... )" follows. 
> What exactly is meant by the last sentence of the introductory paragraph? 
> Must the first match occur in the first stanza of the info?  Does "one single 
> parent device" allow the direct parent only?  Can the attributes belong to the 
> grandparent or great-grandparent?
>
> This is one rule I've tried.  
> SUBSYSTEM=="sound", ATTRS{idVendor}=="0d8c", ATTRS{idProduct}=="0008", SYMLINK+="USBspeakers"
> None of my rules have yielded a SYMLINK.
>
> Thanks for any ideas,                     ... Peter E.

As an alternative to udev, you may already have a persistent name.  When
I plug in a Logitech C170 webcam, /proc/asound/cards shows:
 0 [SB             ]: HDA-Intel - HDA ATI SB
                      HDA ATI SB at 0xfbdf4000 irq 16
 1 [HDMI           ]: HDA-Intel - HDA ATI HDMI
                      HDA ATI HDMI at 0xfbeec000 irq 44
 2 [C170           ]: USB-Audio - Webcam C170
                      Webcam C170 at usb-0000:00:13.2-4, high speed

Then I can record with the webcam microphone by:
arecord -f S16_LE -D hw:C170 filename
So take a look at /proc/asound/cards .