Re: [LAD] snd-usb-audio dying on jackd xruns

Rods Bobavich wrote:
> USB interface is any one of the M-Audio Line. FastTrack USB, FastTrack Pro,
> MobilePre USB... In other words multiple interfaces have been tested. This
> problem is specific to this machine...
>
> ALSA urb.c:480: frame 0 active: -75

Thank you for not mentioning this message on alsa-devel.

In the context of USB, the error code -75 means "babble", which is
a technical term from the USB specification that means that the device
sent some data at a time when it shouldn't (or at least the controller
thinks so).

> ALSA urb.c:146: timeout: still 7 active urbs..
> ALSA urb.c:146: timeout: still 2 active urbs..
> ALSA pcm.c:223: 4:2:1: usb_set_interface failed

As a result of that, the USB controller driver gets wedged.

This looks like a hardware problem with your USB controller. Please try
the latest kernel; there were added some workarounds recently.

You might also try connecting the device through a hub (but there are
some bugs in the EHCI driver which might make it think that it cannot
schedule enough bandwidth for full duplex).

> CE: hpet increased min_delta_ns to 7500 nsec
>
> It seems that the error happened about the time of the hpet increase. Do we
> have a timer problem?

No, this has nothing to do with USB. This message typically occurs on
AMD system with C1E enabled, and is harmless.

Regards,
Clemens

-- 
Don't anthropomorphize computers; they don't like it.
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