Re: USB-1.1 fails with USB 2.0 Hub

From: Juergen Stuber
Date: Fri Nov 12 2004 - 05:47:46 EST

Hi Gregor,

Gregor Jasny <Gregor.Jasny@xxxxxxxx> writes:
> Just a simple me, too.

I don't think it is the same problem.

> I've got the problem with a TerraCAM USB Pro. Plugged
> into my Apple Keyboard it works (with a warning about high power
> consumption). But if I plug it into my Belkin F5U237 the driver complains
> with: "drivers/usb/media/ov511.c: init isoc: usb_submit_urb(0) ret -38".

-38 is -ENOSYS which means "Function not implemented"
(see include/asm-generic/errno.h in the kernel sources).
To support USB 1.1 devices over a 2.0 hub the hub contains
a so-called transaction translator that needs special support
in the USB driver, and which works differently for isochronous
transfers (note the isoc in the error message).
This is usually implemented after the other transfer types.

> Have you already tried another USBv2 hub?

I don't think you can cure it with a different 2.0 hub.
You can either use only 1.1 hubs on the path to the device,
like with the keyboard, or try a newer kernel version
(but then 2.6.9 is already rather new).

Hope this helps


Jürgen Stuber <juergen@xxxxxxxxxxx>
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Looking for consulting and project work in Mozart/Oz, Linux kernel, USB

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