USB locks on laptops.

While I thought it might be an isolated example, I have several
laptops ... all of which lock up their ports when usb devices are
connected.  Typical messages include:

usb3: unrecoverable error, controller halted

and 

usb3: device problem, disabling port 3

... which is an example from a new laptop with usb2.0, but an older
laptop with usb1.0 gives similar messages.

Jun 14 00:09:48 canoe /kernel: uhub0: device problem, disabling port 2

Now... on non-portable hardware, usb ports all seem to work.  All of
my desktop machine's USB ports work just fine with the same hardware.

Any ideas?

Dave.

-- 
============================================================================
|David Gilbert, Velocet Communications.       | Two things can only be     |
|Mail:       dgilbert_at_velocet.net             |  equal if and only if they |
|http://daveg.ca                              |   are precisely opposite.  |
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