[LAU] jackd, libasound_module_pcm_jack.so, custom pcm devices in asoundrc

R Dicaire kritek at gmail.com
Thu Dec 25 16:16:22 EST 2008

Hi folks...Once upon a time, using Ubuntu Edgy, and rebuilding
libasound2 plugins to include libasound_module_pcm_jack.so, I was able
to successfully use skype with jack, using a custom pcm device
specified in .asoundrc:

pcm.skype {
   type plug
   slave {
     pcm "configvoip"

pcm.configvoip {
    type jack
    playback_ports {
      0 system:playback_1
      1 system:playback_2
    capture_ports {
      0 system:capture_1
      1 system:capture_1

The sound card in question is an M-Audio Delta 44 (ice1712).
The above configuration worked flawlessly, but due to issues with
other sound applications using jack, I was forced to attempt various
upgrades of jack, alsa, kernels, and even distributions. Eventually I
settled on Debian Lenny, which includes the alsa jack pcm plugin by
default, unlike Ubuntu, and now have few if any issues with
jack-capable sounds apps. However, I cannot use skype with the above
configuration on any consistent basis because for reasons unknown,
when I make a skype call, and the alsa jack plugin is invoked, that
thread may last a few seconds, the thread dies, and crashes jackd in
doing so.

Currently I'm using a custom RT kernel,, and stock
versions of alsa*/jack* that Debian Lenny uses as of todays date.

alsa-base:                1.0.17dfsg-4
libasound2:              1.0.16-2
libasound2-plugins: 1.0.16-1+b1

libjack:                       0.109.2-3
jackd:                         0.109.2-3

skype:               (yes, I tried 2.x and got same result)

So, some questions. How would I go about troubleshooting the cause of
the dying thread, and subsequent crashing of jackd?

How do I determine the alsa version of the ice1712 driver used in
kernel, alsa website shows 1.0.18a as current driver version.

I can play 16 bit 44k1 wav files fine using aplay -D skype
/path/to/file, from jack_lsp:


Any thoughts, directions, etc would be greatly appreciated, thanks.

aRDy Music and Rick Dicaire present:

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