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

Jörg Müller joerg.mueller7744 at gmail.com
Wed Feb 8 18:16:46 CET 2017

So the bug has been fixed on the alsa-side. However, when I start jack via:

wfs at wfs16:~$ jackd -p 1024 -d alsa -C madifx_record_all -P madifx_playback_all
jackdmp 1.9.10
Copyright 2001-2005 Paul Davis and others.
Copyright 2004-2014 Grame.
jackdmp comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
no message buffer overruns
no message buffer overruns
no message buffer overruns
JACK server starting in realtime mode with priority 10
self-connect-mode is "Don't restrict self connect requests"
Acquire audio card Audio0
creating alsa driver ...
configuring for 48000Hz, period = 1024 frames (21.3 ms), buffer = 2 periods
ALSA: final selected sample format for capture: 32bit float little-endian
ALSA: use 8 periods for capture
ALSA: final selected sample format for playback: 32bit float little-endian
ALSA: use 8 periods for playback
jackd: ../linux/alsa/JackAlsaDriver.cpp:122: virtual int
Jack::JackAlsaDriver::Attach(): Assertion `fCaptureChannels < 256'
Aborted (core dumped)

The corresponding cpp-file at that line compares against a variable
called "DRIVER_PORT_NUM", which is a constant defined in
"common/JackConstants.h" on line 53 on the github repo. Could that be
the problem?

2017-01-23 14:31 GMT+01:00 Adrian Knoth <adi at drcomp.erfurt.thur.de>:
> On Mon, Jan 23, 2017 at 01:57:09PM +0100, Jörg Müller wrote:
>> I need to combine two HDSPe MADI FX cards to one virtual device. I have a
> Fancy!
>> 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
> You can (and probably should) ask this again on the ALSA ML if you want
> to do it via ALSA virtual devices. The other option is to have jack open
> both cards:
>    https://github.com/jackaudio/jack1/commit/40b01cc3691f25840b40432ec16fd312dbfbd365
> I have never tried it, but in theory, you just add -A 2ndALSAname to the
> command line and be done.
> Not sure how much documentation is available for this on the internet,
> but might be worth trying.
> Cheers
> --
> mail: adi at thur.de       http://adi.thur.de      PGP/GPG: key via keyserver

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