[Jackit-devel] Re: [linux-audio-user] jackd and usb 1.1 audio on i386 non-functional

Lee A. Azzarello lee at rockingtiger.com
Fri Mar 3 16:42:35 EST 2006

----- Lee Revell <rlrevell at joe-job.com> wrote:
> On Fri, 2006-03-03 at 23:09 +0200, Sampo Savolainen wrote:
> > On Fri, 2006-03-03 at 13:18 -0500, Lee Revell wrote:
> > > > So, instead of interpreting them to users the software should
> say: "learn C
> > > > headers and read errno.h?". Gah. 
> > > > 
> > > > Good software tells the users what's really wrong and directs
> the user in
> > > > how to fix the issue. This leads to happier users and less
> repeated "why
> > > > doesn't this work" questions on mailing lists, irc, personal
> email, etc.
> > > 
> > > We don't KNOW what's wrong beyond "not enough bandwidth".
> > 
> > "Problems with jackd using your soundcard. Specifically 'Not enough
> > bandwidth'. If you are using an USB soundcard, this probably means
> that
> > you are running the soundcard with either a wrong buffer size or a
> wrong
> > amount of periods. Try running jackd with -r 3"
> > 
> > We don't? I think we do know more. :)
> > 
> "Or maybe you have enabled CONFIG_USB_BANDWIDTH.  Or your kernel is
> buggy.  Or your device is connected through a hub.  The solution may
> depend on which host controller driver you are using..."

Crap. Those are a lot of variables. Perhaps a troubleshooting guide for USB interfaces? The alsa wiki is a total mess on this subject. I don't know enough about the issue to filter out what's true and what's luck but I would like to edit that document to be more conclusive. Here's where I'm at with my setup:

1) CONFIG_USB_BANDWIDTH is not configured
2) Buggy kernel? How do I determine that? the initial test was, I am installing tonight.
3) Device is not connected through a hub
4) the host controller is usb-uhci for controller 1, 2 and 3 then ehci-hcd for a fourth
5) I have not yet tried running jackd with -r 3. I did read that periods with an odd number are deprecated but I did not understand the reason.

Anything other options I might have left out?


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