[alsa-devel] [PATCH] Re: iec958 switch uneffective while playing ac3 stream

Takashi Iwai tiwai at suse.de
Thu Apr 12 21:32:16 CEST 2007

At Thu, 12 Apr 2007 20:25:25 +0200,
Dominique Dumont wrote:
> Takashi Iwai <tiwai at suse.de> writes:
> > After reconsideration, I found it much easier to change the driver to 
> > allow access to the dedicated SPDIF stream even while analog dup
> > mode.  When the SPDIF stream is opened, the SPDIF is forced to reset
> > and then the stream is reserved for the exclusive access until it's
> > closed.
> >
> > The below is a test patch.  Now you see it's so simple...
> >
> > Can anyone test it?
> Done. It does not work:
> $ ac3dec -C -c 1 dh122.ac3
> Using PCM device 'plug:iec958:{AES0 0x2 AES1 0x82 AES2 0x0 AES3 0x2 CARD 1}'
> snd_pcm_open: Device or resource busy
> Output open failed
> I can't find a trace to explain why in kern.log or in syslog.

Are you sure that you are not using the spdif PCM beforehand?
Before running ac3dec, check which PCM substream is being opened.
You can see the PCM substreams in /proc/asound/card0/pcm*p/*


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