RE: [ecasound] Newcomer problem with loop device

Hi Erno,

> Hello,
>
> I am having trouble with loop device. The setup is as follows:
>
> % ecasound \
> -a:master -i:loop,1 -o:jack_auto,alsa_pcm \
> -a:tape -i:jack_generic,audio_in -o:loop,1 \
> -a:mic -i:jack_auto,alsa_pcm -o:loop,1
>
> This results in error message:
>
> (eca-session) Note! Unable to create a valid chainsetup from
> the command-line
> ... arguments.
> (eca-chainsetup) Unable to connect: Chain "tape" is not
> valid. Following errors
>
> ... were detected:
> (eca-chainsetup) Chain "tape" is not connected to any output.
> All chains must have
> ... exactly one valid output. (2.2-NO-CHAIN-OUTPUT)
> (eca-chainsetup) WARNING: Output "loop,1" is not connected to
> any chain.
> ... (3.2-DISCON-OUTPUT)
>
> If I omit either "mic" or "tape" chain, it'll work just fine.
> This must be something very obvious, no? What am I doing wrong here?
>
> --

I'm not sure if this is a bug or the desired behaviour, but as a
workaround, you can do this:

ecasound \
-a:master -i:loop,1 -o:jack_auto,alsa_pcm \
-a:tape -i:jack_generic,audio_in \
-a:mic -i:jack_auto,alsa_pcm \
-a:tape,mic -o:loop,1

Unnecessarily detailed explanation follows :)

The problem is caused by code that attaches outputs to chains
(attach_output_to_selected_chains in eca-chainsetup.cpp). In
pseudo-code, it looks like this:

1. for each output x:
2. if x is the output we want to attach:
3. for each chain c:
4. if c is currently attached to x, disconnect it
5. for each selected chain d:
6. connect x as the output for d

(and similar for inputs in attach_input_to_selected_chains.)

Now, a possible fix is to remove the code that disconnects any chain
currently connected to the output we are concerned with (lines 3 and 4).
This works for the case that Erno described, and I'm pretty sure it
doesn't cause any other problems.

Cheers,
Stuart

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Received on Wed Aug 24 08:15:05 2005