[Discuss-gnuradio] audio_alsa: problem with "valve" at head of audio_alsa sink sub-graph

[Marcus D. Leech]

In my application I have a sub-graph that terminates an an audio_alsa sink.

At the "head" of this sub-graph, I've placed a valve, so that I can turn
off data being
  copied to the audio_alsa sink.

When this valve transitions from "closed" (data flowing) to "open" (data
*not* flowing), it provokes
  the following error in audio_alsa_sink:

audio_alsa_sink[plughw:0,0]: snd_pcm_hw_params failed: File descriptor
in bad state
terminate called after throwing an instance of 'std::runtime_error'
  what():  check topology failed on audio_alsa_sink(1) using ninputs=1,
noutputs


Am I being an idiot here?  Should this work?  If not, why not?

Further, there's a "OK to block" parameter for an audio_alsa_sink.  What
does it do?


-- 
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org