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From: Scott W Gifford <gifford@umich.edu>
To: bluez-users@lists.sourceforge.net
Subject: Re: [Bluez-users] USB/Bluetooth dongle doesn't work in hub
Date: Wed, 01 Dec 2004 19:33:24 -0500	[thread overview]
Message-ID: <qszvfblv8rv.fsf@mspacman.gpcc.itd.umich.edu> (raw)
In-Reply-To: <1099985025.29330.52.camel@pegasus> (Marcel Holtmann's message of "Tue, 09 Nov 2004 08:23:45 +0100")

Marcel Holtmann <marcel@holtmann.org> writes:

[...]

>> As before, they work fine when plugged directly into the laptop.
>
> go ahead and report this problem to the USB mailing list, because it is
> not a Bluetooth problem and I don't know why this fails.

I didn't get an answer on the USB mailing list, but I saw another
related answer that seemed to help.  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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      reply	other threads:[~2004-12-02  0:33 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-11-08 23:44 [Bluez-users] USB/Bluetooth dongle doesn't work in hub Scott W Gifford
2004-11-09  0:11 ` Marcel Holtmann
2004-11-09  0:28   ` Scott W Gifford
2004-11-09  5:47     ` Scott W Gifford
2004-11-09  7:23       ` Marcel Holtmann
2004-12-02  0:33         ` Scott W Gifford [this message]

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