[Jack-Devel] Cannot combine audio devices with more than 64 channels

Jörg Müller joerg.mueller7744 at gmail.com
Mon Jan 23 13:57:09 CET 2017

I need to combine two HDSPe MADI FX cards to one virtual device. I have a
working driver, which is alsa-compatible. I can select each single card in
any alsa-compatible application and all channels work flawless.
For combining the MADI FX cards to one virtual device, I created an
.asoundrc with 194 inputs for each card. When I start that virtual device
jackd -R -d alsa -C madifx_record_all -P madifx_playback_all

I get this error:
> creating alsa driver ...
> jackd: pcm_multi.c:1060: snd_pcm_multi_open: Assertion
`!slave_map[sidxs[i]][schannels[i]]' failed.

However, it works when I reduce the amount from 194 to 64 channels per
card. I tried to use 128 channels per card, but that fails the same way.
See my alsa-info attached, which also includes the .asoundrc content.

I also found this, which might be related:

To me, this looks like a bug. What do you think?
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