Re: [Discuss-gnuradio] Audio_alsa_sink question

[Eric Blossom]

On Thu, Jan 15, 2009 at 01:52:08PM +0200, Sebastiaan Heunis wrote:
> Hi
> 
> I have a problem with the audio sink.  I'm playing around with the
> analysis_filterbank block.  I have a GUI allowing the user to pick a
> channel.  That channel then gets connected to an FM demodulator,volume
> control and finally an audio sink.  At the start of the app, I
> initialise everything and the audio sink works.  As soon as I change a
> channel by reconnecting everything, I get this error:
> 
> 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(8) using
> ninputs=1, noutputs=0
> Aborted
> 
> Can someone please tell me what might be wrong?
> 
> Thanks.
> Sebastiaan

That's a bug in the implementation of gr-audio-alsa.
If you look in the code you'll find a couple of FIXMEs.
One of those is the thing you've stumbled on to.

Eric