[pulseaudio-discuss] Maximum concurrent connection limit on PA 0.9.13?

Andrew Gault abgault at gmail.com
Wed Dec 3 13:44:55 PST 2008


I've run into some weird behaviour in pulseaudio that looks like it  
could be easily explained by a per user connection limit. I can't find  
anything in the docs to configure this though, I hope someone here  
knows and I've just missed something obvious.

I am using pulseaudio on a headless Ubuntu 8.04 server to capture and  
encode audio from multiple applications simultaneously. I have  
configured multiple null sinks, and route each application to a  
different sink; I then connect to the null sink monitor using the PA  
Simple API and encode. It works perfectly for the first few  
application/encoder combinations, but consistently fails to connect  
after a certain number with an "Access denied" error. All applications  
and encoders use the same user who is a member of the pulse-access  

Originally using the 0.9.10 package from the Ubuntu 8.04 repositories  
this happened on the 23rd app/enc pair (so 64 connections), every  
time. Due to sound quality issues I upgraded using the 0.9.13 source,  
and now the connections consistently fail on the 7th app/enc pair, on  
connection 14. Any attempts to connect thereafter also error with  
"Access denied".

For each failed connection, the daemon writes two lines to the log:
	client.c: Freed 19 "Native client (UNIX socket client)"
	protocol-native.c: Connection died.

If I disconnect a few app/enc pairs I can then reconnect again back up  
to the limit. It really seems like a hard concurrent connection limit.

I tried configuring module-native-protocol-unix to allow anonymous  
authorisation. This let the 7th app/enc pair connect OK, but on the  
8th pair (connection 15) the error "Connection terminated" is  
returned, and the daemon proceeds to shut himself down with no obvious  
reason appearing on the log. I.e.:
	sink.c: Freeing sink 0 "tk1"
	source.c: Freeing source 0 "tk1.monitor"
	module.c: Unloaded "module-null-sink" (index: #0).
And so on for the rest of the modules - it looks like a normal shutdown.

I am starting with the command:
sudo pulseaudio --system --daemonize --high-priority --log- 
target=syslog --disallow-module-loading=1 --log-level=debug --disallow- 
exit --exit-idle-time=-1

My default.pa/system.pa looks like:
load-module module-null-sink format=s16le rate=44100 channels=2  
load-module module-null-sink format=s16le rate=44100 channels=2  
load-module module-null-sink format=s16le rate=44100 channels=2  
load-module module-native-protocol-unix

Can anyone help?

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