[LAD] USB device dmesg error

[Clemens Ladisch]

tom at trellis.ch wrote:
> -> the "Couldn't open device" looks suspicious

I guess you are not root.

>         bmAttributes           37
>           Transfer Type            Isochronous
>           Synch Type               Asynchronous
>           Usage Type               Implicit feedback Data

>> I guess this is one of the devices that use implicit feedback
>> synchronization, which is very buggy in the current driver.  As far as
>> I know, only Jack works with these devices.
>
> Huh? How could that work with JACK if it doesn't with ALSA?

Jack uses ALSA; that driver code was tested only with Jack, and
expects the playback and capture streams to be opened at the same
time.

> Btw, this is what i get when trying to start JACK with it:
>
> ATTENTION: The capture device "hw:0,0" is already in use. The following
> applications  are using your soundcard(s) so you should  check them and
> stop them as necessary before  trying to start JACK again:
>
> jackd (process ID 2341)

Even more bugginess.  Maybe try the other Jack.

A patch series that should fix the bugs was posted on alsa-devel:
http://mailman.alsa-project.org/pipermail/alsa-devel/2013-August/065744.html


Regards,
Clemens