Re: [Ltsp-discuss] Sound just broke on Ubuntu 11.10 Oneiric, LTSP 5.2.16-0ubuntu7

[Jan M. <ja...@re...>]

On 13-06-12 08:28, Philip Loewen wrote:
> Unfortunately I don't really understand how pulseaudio is supposed to
> work across the network. Should a pulseaudio process be running also on
> the LTSP server?

Seems like you have figured out most of it already.

See pulseaudio as a sound 'server'.  It provides a way for applications 
to play sound.  The applications connect to the pulseaudio server, and 
pulseaudio directs that sound to an output device (a soundcard).  The 
pulseaudio server should therefor always be running on the machine which 
has access to the sound device.

In LTSP's case, applications running on the server, connect to 
pulseaudio running on the client, and pulseaudio there sends the audio 
to the local soundcard.  So the pulseaudio process should be running on 
each client, and not on the server (unless you want to use the soundcard 
in the server, for whatever reason - but that's another story).

You've already found the PULSE_SERVER export - that's how the server 
applications know where to send their audio streams to.  You can use the 
command 'pactl' to connect to and control the server specified in 
PULSE_SERVER.  For example, 'pactl info' shows the status of the 
pulseaudio server.  As you've already determined the server isn't 
running on your client, this will not return anything useful.

And that concludes this drive-by introduction to pulseaudio in LTSP.  As 
for the specific problem you're having - the question you should be 
asking yourself is: what have you changed since the last time you ran 
ltsp-update-image?  My experience is that usually these things do not 
happen 'spontaneously', despite obvious appearances.

About your error:  the LTSP code that is responsible for starting the 
pulseaudio daemon, can be found in 
/opt/ltsp/<arch>/usr/share/ltsp/ltsp-init-common.  You can find some 
pointers there, such as the exact arguments that LTSP uses to launch 
pulseaudio.  You will see it calls pulseaudio with very different 
arguments than you used in your test case, therefor your test case (and 
any error messages you get from it) are unreliable.

 From the ltsp-init-common file, you can also see that LTSP instructs 
pulseaudio to log to the syslog - so be sure to check /var/log/syslog on 
the client.  That's where the pulseaudio startup error messages will 
be.  It might be the same as your test case... but then it might just 
not be.

Kindest regards,

Jan Middelkoop
Recreatie en Zorg Groep B.V.

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