[linux-audio-user] USX2Y rawusb mode

Karsten Wiese annabellesgarden at yahoo.de
Thu Mar 3 06:41:17 EST 2005

Am Sonntag 27 Februar 2005 04:35 schrieb Spencer Russell:
> Ok, scratch what I said about it not crashing anymore. It's still
> quite less than stable. I was using qjackctl, and it was fine
> until I started pd, at which point my computer froze. So I
> rebooted, and started jackd without qjackctl
> sudo jackd -R -dalsa -dhw:0,0 -p1024 -n2 -i2 -o2
> and was using it fine for a while, I started pd without problems,
> then I was trying to figure out how to connect to the midi port
> of PD when the following appeared on /var/log/mesages:
> Feb 26 22:26:10 slingshot kernel: ALSA /usr/src/alsa/   \
> alsa-driver-1.0.8/alsa-kernel/usb/usx2y/usbusx2yaudio.c:199:   \
> usb_submit_urb() returned -11
can you check if this error doesn't happen, when modprobing like 
	$ modprobe snd_usb_usx2y nrpacks=4
nrpacks=1 and "rawusb mode" are irrelevant if you run jack with moderate latencies
as above "-p1024 -n2" and 2 inputs.

What kernel are you using? If its not 2.6.11 you might give that a try.

> apon closer reading of the responses to my earlier question about
> getting capture channels 3 and 4 to work, it looks like there're
> 2 different usx2y drivers? I'm using whatever came with alsa
> 1.0.8, and the changelog says that they include rawusb support,
> so I think I'm using the correct one. But it'd be kinda nice if
> I'm not, cause that's an easy fix.
its 2 jack drivers for usx2y.
my first implementation doesn't really differ from whats in 
jack's alsadriver now, if you apply the patch below.
kernel wise make shure that
	$modinfo snd-usb-usx2y
gives you
	"TASCAM US-X2Y Version"

Recommendation for basic setup:

When you use jack with "-p1024 -n2" and 2 ins are enough just ignore the "rawusb hipe" ;-)
Do 1.
	$ modprobe snd_usb_usx2y nrpacks=4
and then 2.
	$ jackd -R -dalsa -dhw:0 -p1024 -n2 -i2 -o2

that will give you 2 ins & 2 outs. but channels 3+4 in will not work.
I strongly suggest you get this simpler case going first.

if that works reliably, proceed with more aggressiv nrpacks settings
	$ rmmod snd_usb_usx2y (will propably have to end some processes first)
	$ modprobe snd_usb_usx2y nrpacks=2
check if its ok still......
and finally
	$ rmmod snd_usb_usx2y (will propably have to end some processes first)
	$ modprobe snd_usb_usx2y nrpacks=1

Only on success and if you want channels 3+4 or low latencies, proceed with the following:

1. Patch jack's alsa driver, compile and install it:
--- alsa_driver.c.~1.65.~       2005-02-22 01:15:07.000000000 +0100
+++ alsa_driver.c       2005-02-22 01:16:32.000000000 +0100
@@ -450,7 +450,7 @@
        if ((err = snd_pcm_hw_params_set_channels (handle, hw_params,
-                                                  *nchns)) < 0) {
+                                                  2 /* *nchns*/)) < 0) {
                jack_error ("ALSA: cannot set channel count to %u for %s",
                            *nchns, stream_name);
                return -1;
	$ modprobe snd_usb_usx2y nrpacks=1
	$ jackd -R -dalsa -dhw:0,2

have fun

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