Can't link multiple streams

Can't link multiple streams

[Robert Brückmann]

I have 3 capture and 3 playback devices (all sample-synced via 
wordclock) which I want to sync via snd_pcm_link(). So I do the 
following calls:

snd_pcm_link(playback1,playback2);
snd_pcm_link(playback2,playback3);
snd_pcm_link(capture1,capture2);
snd_pcm_link(capture2,capture3);
snd_pcm_link(playback1,capture1);

This worked in an older version of ALSA without problems (I used 
0.9.0beta12), but since I upgraded to 0.9.7a, I can't link, the last 
link operation gives an error:

ALSA lib pcm.c:1148:(snd_pcm_link) SNDRV_PCM_IOCTL_LINK failed: 
Operation already in progress

How can I do the linking in current Alsa versions?

Thanks,
Robert



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Re: Can't link multiple streams

[Takashi Iwai]

At Mon, 10 Nov 2003 17:09:40 +0100,
Robert Brückmann wrote:
> 
> I have 3 capture and 3 playback devices (all sample-synced via 
> wordclock) which I want to sync via snd_pcm_link(). So I do the 
> following calls:
> 
> snd_pcm_link(playback1,playback2);
> snd_pcm_link(playback2,playback3);
> snd_pcm_link(capture1,capture2);
> snd_pcm_link(capture2,capture3);
> snd_pcm_link(playback1,capture1);
> 
> This worked in an older version of ALSA without problems (I used 
> 0.9.0beta12), but since I upgraded to 0.9.7a, I can't link, the last 
> link operation gives an error:
> 
> ALSA lib pcm.c:1148:(snd_pcm_link) SNDRV_PCM_IOCTL_LINK failed: 
> Operation already in progress

which link in the above do you have this error?


Takashi


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Re: Can't link multiple streams

[Jaroslav Kysela]

On Mon, 10 Nov 2003, [ISO-8859-1] Robert Brückmann wrote:

> I have 3 capture and 3 playback devices (all sample-synced via
> wordclock) which I want to sync via snd_pcm_link(). So I do the
> following calls:
>
> snd_pcm_link(playback1,playback2);
> snd_pcm_link(playback2,playback3);
> snd_pcm_link(capture1,capture2);
> snd_pcm_link(capture2,capture3);
> snd_pcm_link(playback1,capture1);
>
> This worked in an older version of ALSA without problems (I used
> 0.9.0beta12), but since I upgraded to 0.9.7a, I can't link, the last
> link operation gives an error:
>
> ALSA lib pcm.c:1148:(snd_pcm_link) SNDRV_PCM_IOCTL_LINK failed:
> Operation already in progress
>
> How can I do the linking in current Alsa versions?

This is wrong sequence. Try:

snd_pcm_link(playback1,playback2);
snd_pcm_link(playback2,playback3);
snd_pcm_link(playback3,capture1);
snd_pcm_link(capture1,capture2);
snd_pcm_link(capture2,capture3);

or:

snd_pcm_link(playback1,playback2);
snd_pcm_link(playback1,playback3);
snd_pcm_link(playback1,capture1);
snd_pcm_link(playback1,capture2);
snd_pcm_link(playback1,capture3);

It's true that semantics changed a bit. The stream being added shouldn't
be linked.

						Jaroslav

-----
Jaroslav Kysela <perex@suse.cz>
Linux Kernel Sound Maintainer
ALSA Project, SuSE Labs


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