dara <[EMAIL PROTECTED]> writes:

> Hi,
>
> I just wanted to report that I get this behaviour also. 

[...]

> I had also noticed when I got the dongle initially about 3 months ago
> that it worked when directly connencted to the laptop, but not when
> connected to the hub.

Hi Dara,

It's been a while since you asked your question, but here's an answer
anyways.

Apparently using certain types of transfers on a high-speed hub with a
low-speed device is still unsupported:

  http://www.linux-usb.org/usb2.html

    In terms of functionality, the latest driver:

    [...]

    * Has partial support for split transactions (full and low speed
      transfers) through USB 2.0 hubs:

    [...]

      o You can't (yet) use full speed isochronous transfers through
        USB 2.0 hubs. (At least without an experimental patch.)  That
        means: don't hook up USB 1.1 webcams, speakers, etc. to high
        speed buses, they'll enumerate but you won't be able to use
        them otherwise. Eventually of course a dozen USB 1.1 webcams
        will easily coexist at full data rate on a single USB 2.0 bus,
        using USB 2.0 hubs.

The "ehci-hcd" module provides support for high-speed USB 2.0.
Removing it with rmmod makes everything run as low-speed USB 1.x, and
that seems to solve the problem.

I tested with the dongles I have: D-link DBT-120, Belkin F8T001,
AmbiCom BT2000, and IOGear GBU211.  I tested plugged directly in,
plugged into a hub connected directly, and plugged into a hub
connected to a hub connected to a hub connected directly.

-----ScottG.


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