How do I use pulseaudio's module-sine properly?

Question

I tried loading the module like this

pactl load-module module-sine

It sounds terrible! Lots of clicks and pops on top of the sine sound

I'm running this environment

$ uname
Linux vitalsine3h 3.10.29+ #636 PREEMPT Sun Feb 9 19:58:58 GMT 2014 armv6l GNU/Linux

$ pactl --version
pactl 2.0
Compiled with libpulse 2.0.0
Linked with libpulse 2.0.0

I've also tried building pulseaudio 4

$ ./pactl --version
pactl 4.99.3-4-g3cc4
Compiled with libpulse 4.99.0
Linked with libpulse 4.99.0

Which sounds very similar.

So how can I get a nice sine wave from pulseaudio?

Answer 1

I am having some luck (with 4.99) setting tsched to false when loading the alsa-card module

pi@pi $ ./pactl load-module module-alsa-card device_id=0 tsched=false
16
pi@pi $ ./pactl load-module module-sine
17

However, pulseaudo is outputting these messages

E: [alsa-sink-bcm2835 ALSA] alsa-sink.c: ALSA woke us up to write new data to the device, but there was actually nothing to write!
E: [alsa-sink-bcm2835 ALSA] alsa-sink.c: Most likely this is a bug in the ALSA driver 'snd_bcm2835'. Please report this issue to the ALSA developers.
E: [alsa-sink-bcm2835 ALSA] alsa-sink.c: We were woken up with POLLOUT set -- however a subsequent snd_pcm_avail() returned 0 or another value < min_avail.

And silently exits after 20 seconds. I need to stop it exiting

EDIT:

passing --exit-idle-time=-1 on pulseaudio commandline seems to stop the exiting. Not sure how it detects idle, but it doesn't work for this usecase.