[LAD] JACK on Gigaport HD+ at 4800kHz (reduced channel count)

Fons Adriaensen fons at linuxaudio.org
Tue Feb 25 15:52:28 UTC 2014

On Tue, Feb 25, 2014 at 10:09:16AM -0500, Paul Davis wrote:
> the option doesn't alter what the JACK backend sees from ALSA (or
> wherever). it changes which channels get represented by JACK ports.

Wrong. If things were as you claim, this should just work:
(on a 64-ch card)

fons at hypatia:~> jackd -P70 -p256 -t2000 -u -dalsa -dhw:0,0 -r48000 -p256 -n2 -i16 -o16
ALSA: cannot set channel count to 16 for capture
ALSA: cannot configure capture channel
cannot load driver module alsa

The -i and -o values ARE used as parameters to ALSA, and
not just to determine how many of the available channels 
are mapped to Jack ports. You can also verify this in the



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