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

John Rigg j at jrigg.co.uk
Wed Feb 8 20:47:20 CET 2017


On Wed, Feb 08, 2017 at 06:16:46PM +0100, Jörg Müller wrote:
> 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"
> audio_reservation_init
> Acquire audio card Audio0
> creating alsa driver ...
> madifx_playback_all|madifx_record_all|1024|2|48000|0|0|nomon|swmeter|-|32bit
> 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'
> failed.
> 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?

It looks like the line

#define DRIVER_PORT_NUM 256

is causing the problem.

I only have 24 input and output channels on my hardware, so I just tried
recompiling jack2 with DRIVER_PORT_NUM 24 and it gives the same type of
error.

John



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