====== Getting USB Audio to work ======

This guide explains how to connect a generic linux-compatible USB sound card to the CH3SNAS/DNS-323. In this example, a Conceptronic USB Sound adapter was used. It is a thumbdrive-size usb-stick based on the C-Media CM108 chipset, and features a stereo in- and output jack.

I am not an expert on this subject, so please feel free to correct this page if you feel the need to do so.

==== Installing Drivers ====

You will need to install the following kernel modules:

  insmod kernel/sound/soundcore.ko;
  insmod kernel/sound/core/snd-page-alloc.ko;
  insmod kernel/sound/core/snd.ko;
  insmod kernel/sound/core/snd-hwdep.ko;
  insmod kernel/sound/core/snd-timer.ko;
  insmod kernel/sound/core/snd-pcm.ko;
  insmod kernel/sound/core/oss/snd-mixer-oss.ko;
  insmod kernel/sound/core/oss/snd-pcm-oss.ko;
  insmod kernel/drivers/usb/class/audio.ko;
  insmod kernel/sound/core/seq/snd-seq-device.ko;
  insmod kernel/sound/core/snd-rawmidi.ko;
  insmod kernel/sound/usb/snd-usb-lib.ko;
  insmod kernel/sound/usb/snd-usb-audio.ko;

Precompiled modules for firmware v1.03 can be found here: http://dev.skcserver.de/dns323/modules_v1.03/ (except for audio.ko).

Load the modules using insmod in the order listed above. You can cd into the modules-directory and copy/paste the lines above in your terminal. Plug in your sound card. Typing dmesg in the command line should show you something like this:
  usbcore: registered new driver snd-usb-audio
and some entries for usbaudio.

==== Create entries in /dev ====
Now you can chroot into debian. Create the devices in /dev like so:

  cd /dev
  mknod -m 660 mixer c 14 0; chgrp audio mixer
  mknod -m 660 mixer1 c 14 16; chgrp audio mixer1
  mknod -m 660 dsp c 14 3; chgrp audio dsp
  mknod -m 660 dsp1 c 14 19; chgrp audio dsp1

(taken from http://buffalo.nas-central.org/index.php/Add_a_USB_sound_card)


apt-get install sox and see if you can make some sound (substitute $1 for a sound file on the NAS):

  sox -q $1 -t ossdsp /dev/dsp


== Sources ==
  * http://buffalo.nas-central.org/index.php/Add_a_USB_sound_card
  * http://sokrates.mimuw.edu.pl/~sebek/openwrt/
  * http://wiki.openwrt.org/UsbAudioHowto