[linux-audio-user] US428 Channels 3 and 4

Rui Nuno Capela rncbc at rncbc.org
Mon Feb 21 12:09:16 EST 2005

Spencer Russell wrote:
> The US428 has 4 capture channels and 2 playback channels. Capture
> channels 3 and 4 are switchable between analog and digital. The
> button to switch doesn't seem to do anything, though.
> -spencer
> On Mon, Feb 21, 2005 at 09:05:32AM +0000, Rui Nuno Capela wrote:
>> BTW, shouldn't the US-428 have 8 playback channels, the US-224 have 4,
>> and finally 2 for US-122?

I took a quick look into Karsten's original jackd usx2y_driver code and...
I'm affraid that the number of channels were being hardcoded as 2 for
capture and 2 for playback.

OTOH already in the current jack CVS trunk, the number of channels are
either given on the jackd command line (-i,-o) or taken from the maximum
allowed by the ALSA driver (via snd_pcm_hw_params_get_channels_max()).
Maybe its around here where the issue is? Karsten?

I could also check that the jackd usx2y specific code has support for no
more than 4 capture and 2 playback channels.

What happens when you start jackd explicitly for 4 input channels (-i4)?
e.g. jackd -R -d alsa -d hw:N[,2] -i4 -o2

I'll remember to try this myself, when I get home.

Take care.
rncbc aka Rui Nuno Capela
rncbc at rncbc.org

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