USB Problems, was Re: [ltp] Gpsd & friends

[U Kuehn]

Marius Gedminas wrote:
> 
> (USB on old T42 broke down in an interesting way: USB1 devices work
> normally, but USB2 devices fail.  I think it's a hardware failure,
> although I'm not quite sure how it can be.)
> 
There is a well-known hardware-related bug that looks like that. Had it
on my own machine. Even USB2 devices would sometimes work, but not
reliably.

I found a reference saying that this was caused by the design flaw in
the southbridge being not as well-protected against static electricity
as it should be.

If your system still has warranty, return it for repair (but check e.g.
with a windows system first that it is really the hardware). A quick
work-around is to unload the ehci-hcd module. However, only USB1 speed,
which is a pain for mass storage. My system board got replaced, after
some more wierdness: the sound hardware sometimes disappeared from the
system (also located in the south bridge), and months later the system
rather reliably crashed. At that point the problem could be easily
reproduced at the repair site :)

Hope this helps
Ulrich