[pulseaudio-discuss] usb audio on nslu

Lennart Poettering lennart at poettering.net
Thu Oct 25 16:33:16 PDT 2007

On Sat, 20.10.07 18:12, Martin Uecker (muecker at gmx.de) wrote:

> Hi,
> I am trying to redirect the sound of my notebook to
> an usb sound card (soundblaster) connected to a NSLU.
> This does not work because somehow pulseaudio (version:
> Version: 0.9.6-2 from Debian unstable) produces
> only a series of slowly repeated clicks. When I connect
> the usb sound card directly to the notebook a pulseaudio
> daemon (version 0.9.6-1ubuntu2 from gutsy) running on the
> notebook can use it without problems. mpd on the NSLU can
> use the sound card without problems too.
> Any suggestions how to debug this?

Hmm, yeah. Could you please check the CPU load PA imposes on the NSLU?

It might be a good idea to increase the fragment size used by PA by a
big margin. Also, make sure to enable RT scheduling.

PA is not really prepared to work on embedded CPUs, where
libatomic_ops emulates atomic ops with mutexes and where the kernel is
compiled with small HZ.

Especially with 0.9.7 make sure to run a a kernel with HZ=1000 with
preempt enabled, and run PA as RT process for optimal results.


Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
http://0pointer.net/lennart/           GnuPG 0x1A015CC4

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