Re^2: A persistent name for a sound device.

[Ralf Mardorf <ralf.mardorf@alice-dsl.net>]

On Tue, 2014-02-04 at 08:57 -0800, peter@easthope.ca wrote:
> Alan,
> 
> *	From: Alan Greenberger 
> *	Date: Mon, 3 Feb 2014 09:34:42 -0500
> > 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
> 
> Suppose you reboot the machine without changing the hardware. 
> Does each device always retain its card number across the reboot?
> In my case no.  Consequently I can reboot and find that the 
> VoIP ring is being sent to the headset.  Not acceptable.
> 
> A persistent name remains associated with a specific device 
> across a reboot.

As already mentioned before, this is done by 

/etc/modprobe.d/alsa-base.conf 

my e.g. does look like that:

Arch Linux 64-bit

[rocketmouse@archlinux ~]$ cat /etc/modprobe.d/alsa-base.conf
# ALSA module ordering
options snd slots=snd_hdspm,snd_ice1712,snd_ice1712

Debian 32-bit

[rocketmouse@archlinux ~]$ cat /mnt/debi386/etc/modprobe.d/alsa-base.conf
# autoloader aliases
install sound-slot-0 /sbin/modprobe snd-card-0
install sound-slot-1 /sbin/modprobe snd-card-1
install sound-slot-2 /sbin/modprobe snd-card-2
install sound-slot-3 /sbin/modprobe snd-card-3
install sound-slot-4 /sbin/modprobe snd-card-4
install sound-slot-5 /sbin/modprobe snd-card-5
install sound-slot-6 /sbin/modprobe snd-card-6
install sound-slot-7 /sbin/modprobe snd-card-7
# Cause optional modules to be loaded above generic modules
install snd /sbin/modprobe --ignore-install snd && { /sbin/modprobe --quiet snd-ioctl32 ; /sbin/modprobe --quiet snd-seq ; : ; }
install snd-rawmidi /sbin/modprobe --ignore-install snd-rawmidi && { /sbin/modprobe --quiet snd-seq-midi ; : ; }
install snd-emu10k1 /sbin/modprobe --ignore-install snd-emu10k1 && { /sbin/modprobe --quiet snd-emu10k1-synth ; : ; }
# Keep snd-pcsp from beeing loaded as first soundcard
options snd-pcsp index=-2
# Keep snd-usb-audio from beeing loaded as first soundcard
options snd-usb-audio index=-2
# Prevent abnormal drivers from grabbing index 0
options bt87x index=-2
options cx88_alsa index=-2
options snd-atiixp-modem index=-2
options snd-intel8x0m index=-2
options snd-via82xx-modem index=-2
# ALSA module ordering
options snd slots=snd_hdspm,snd_ice1712,snd_ice1712

Since Debian comes with default crap, the OP likely needs to remove

# Keep snd-usb-audio from beeing loaded as first soundcard
options snd-usb-audio index=-2

and add something like

options snd slots=snd_usb_audio,snd_driver_x,snd_driver_y,snd_driver_n