WARNING: Latest Linphone on Arch breaks device access

Janina Sajka janina at rednote.net
Wed Sep 7 15:32:57 EDT 2016


Chris:

You've put me on the trail of docs I've looked for and failed to find
forever.

I'm now looking at:
http://alsa.opensrc.org/MultipleCards


If I'm reading this correctly, I should be able to get the results I
need by specifying a vendor and product id to order my two usb cards
like I want them ordered.

Very cool. Hope it works!

Janina


Chris Brannon writes:
> Janina Sajka <janina at rednote.net> writes:
> 
> > It was a great suggestion, Chris. Unfortunately, it seems there's yet
> > another bug in how alsa handles usb devices.
> >
> > I have 2 usb devices. No matter how I specify things, the card that gets
> > invoked is the first of those two.
> 
> Oh interesting.  So it looks like there's a name clash.
> Last time I dealt with multiple USB audio devices, they had unique
> human-friendly IDs by default.  My Logitech USB headset was called
> Headset, and my FM transmitter was called RocketFM.
> Apparently I was just lucky.
> 
> Not sure how much you know about alsa, so I'll also mention that
> you can see the human friendly IDs by looking for the symlinks in
> /proc/asound.  They're also listed in the output of aplay -l, but it's
> sort of non-intuitive what they are.
> 
> > Now, if I were really clever, I suppose I'd know how to write udev rules
> > to insure that the Sennheiser gets a lower card ID than the C-Media
> > device.
> 
> Well if you send me the output of lsusb, I can probably write some udev rules
> for you.  Or alternatively have a look at http://alsa.opensrc.org/Udev for a
> starting point.
> 
> -- Chris
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-- 

Janina Sajka,	Phone:	+1.443.300.2200
			sip:janina at asterisk.rednote.net
		Email:	janina at rednote.net

Linux Foundation Fellow
Executive Chair, Accessibility Workgroup:	http://a11y.org

The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI)
Chair, Accessible Platform Architectures	http://www.w3.org/wai/apa



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