Multiple USB ethernet devices on one usb port (with hub)?

[Bernd Walter]

On Sat, Sep 27, 2003 at 10:34:04AM -0700, Andrew Thomas wrote:
> --- Ian Dowse <iedowse at maths.tcd.ie> wrote:
> > There is definitely one problem that stops you from using two
> > identical USB ethernet devices, but I don't know if it's the only
> > one: the "axe" driver uses a static (global) stucture for some
> > per-interface data, so it clobbers this state with two interfaces.
> > 
> > I had said to Bill Paul (cc'd) that I would suggest a patch to fix
> > this, but I never managed to get my two USB ethernet interfaces in
> > the same place at the same time to test them! Would you be able to
> > try out the following patch to see if it helps? Just apply it in
> > /usr/src and rebuild the kernel.
> 
> To follow up on this...
> 
> I tried Ian's changes to no avail.  I applied the patches and rebuilt
> the kernel.  Upon rebooting with both netgear fa120 ethernet devices
> attached (with the new axe driver), both devices are recognized, one
> is configured and nothing works (i.e., in spite of the one device
> being configured, it is dead).

You might take power consumption into acount.
If your hub is not powered it can't supply more then 100mA per port.
check the required consumption of  your ethernet devices with
usbdevs -v.
In case they require more then 100mA you *must* use a self powered
hub.
Many cheap hub lie about their power state, but that doesn't change
the requirements at all.

-- 
B.Walter                   BWCT                http://www.bwct.de
ticso at bwct.de                                  info at bwct.de