Rescanning USB bus?

Hi all,

I'm using Angstrom distribution along with a 'vernier' cable to run
the USB port in host mode.

Does anyone else have problems when disconnecting / reconnecting
peripherals? Seems ok if I boot with a peripheral connected, however
if I remove it, you get a usb-disconnect in the log and won't

This is using the 24-Aug uImage from Koen's Angstrom-distribution demo

Is there any way of rescanning / resetting the USB bus ?



Bit more info... its just the Beagleboard itself where this is a
problem. With a hub you can plug/unplug from the ports on the hub.
But you must leave the hub plugged into the Beagle.

I have had similar problems, in this case with a cheap hub. It's
externally powered, but uses the same 5V regulated supply as the
BeagleBoard itself.

I think the problem is that plugging in a USB device causes the +5V
supply to dip momentarily as the capacitors in the newly plugged-in
device steal charge. I've seen a small glitch on a good oscilloscope:
0.3V drop over 2 us, which really shouldn't hurt anything but maybe
it's worse sometimes.

It seems that either USB doesn't have a "slow start" spec or cheap
hubs and devices don't comply with it.

A command to reset/rescan the USB would be helpful indeed!