Re: snd-usb-usx2y 0.8.7 hwdep pcm oopses!

[Takashi Iwai <tiwai@suse.de>]

At Wed, 15 Dec 2004 14:05:05 -0000 (WET),
Rui Nuno Capela wrote:
> 
> Hi Karsten,
> 
> >   jackd -d usx2y -d hw:n,2 ... returns a 'resource busy' condition.
> >
> > Without the 0.8.7.1 patch, it works BUT iif n < 2; if n >= 2, I get the
> > 'hwdep' assertion failure on jackd; aplay crashes on either value of n.
> >
> > With the patch applied, I always get the "resource busy" error on 'jackd
> > -d usx2y -d hw:n,2 ...' and on 'aplay -D hw:n,2 ...'.
> >
> > So, the sacred question is: How can I make jackd to work with the "rawusb"
> > interface?
> >
> > Just a clueless question: does it need a newer version for the jackd usx2y
> > backend driver? I'm still using your's original one you've ever posted.
> > I've been maintaining it as a jack patch and can be found on my personal
> > home server (http://www.rncbc.org/usx2y/jack-0.99.35-usx2y.patch.gz).
> >
> 
> I found the culprid, almost for sure.
> 
> On jack/drivers/usx2y/usx2y_driver.c:2158, you may find there's this
> hardcoded:
> 
>     snd_hwdep_open(&driver->hwdep_handle, "hw:1,1", O_RDWR);
>                                            ^^^^^^
> 
> so I guess this could only work if snd-usb-usx2y is your second soundcard
> (index=1). Indeed it was on all my successful tests. That explains a lot
> of trouble.
> 
> Simple dummy question: how can I avoid that hardwiring, and fill in the
> proper soundcard index number n, as in "hw:n,1" ? In other words, how can
> I retrieve that number, given the alsa device name (e.g. str="hw:2,2")
> without going dirty as in sscanf(str, "hw:%d", &n); ?

You can get the card number from ctl or pcm instance.
Check snd_*_get_card() functions.


Takashi


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