Re: [Dorset] Using Two USB Audio Adaptors and Selecting the Right One Programatically

[Terry Coles]

On Saturday, 10 March 2018 14:08:41 GMT Ralph Corderoy wrote:
> I can't tell if that includes my suggestion.  :-)

Well I did say that I'd been using udev rules.

> Why would they?  I thought the udev rules were mapping from a USB port
> to a textual label.  You then ditch the hw:card,device number and use

As mentioned previously, labels only work with aplay and omxplayer, which 
don't support Python lists or looping through a list.
 
> hw:label,device.  Are you only using the Pi for these trials, or

I'm using both.  It's easier to observe results and copy'n'paste from this 
machine than from the Pi.

> switching away from Raspbian?  What's your udev look like after
> following that guide?

Raspbian is the goal.

Here is the contents of /etc/udev/rules.d/70-alsa-permanent.rules:

SUBSYSTEM!="sound", GOTO="my_usb_audio_end"
ACTION!="add", GOTO="my_usb_audio_end"

ATTRS{idVendor}=="8086", ATTRS{idProduct}=="0808", ATTR{id}="TOWER"
ATTRS{idVendor}=="0d8c", ATTRS{idProduct}=="013c", ATTR{id}="CHANCEL"

LABEL="my_usb_audio_end" 

I've tried making the ATTR{id}=0 or 1 and that makes no difference.

Here is the contents of /etc/asound.conf:

pcm.!default {
        type hw
        card 0
        device 0
}

ctl.!default {
        type hw
        card 0
        device 0
}

pcm.TOWER {
    type hw
    card 0
        device 0
}

ctl.TOWER {
    type hw
    card 0
        device 0
}

pcm.CHANCEL {
    type hw
    card 1
        device 0
}

ctl.CHANCEL {
    type hw
    card 1
        device 0
}

I've also tried naming the Cards instead of using numbers.

-- 



                Terry Coles

-- 
Next meeting:  Bournemouth, Tuesday, 2018-04-03 20:00
Meets, Mailing list, IRC, LinkedIn, ...  http://dorset.lug.org.uk/
New thread:  mailto:dorset@mailman.lug.org.uk / CHECK IF YOU'RE REPLYING
Reporting bugs well:  http://goo.gl/4Xue     / TO THE LIST OR THE AUTHOR