Re: USB Mass Storage devices continually reenumerate

On 10/17/07, Felipe Balbi <[email protected]> wrote:
> Hi,
>
> On 10/17/07, Mike Nuss <[email protected]> wrote:
> > I'm seeing some flaky behavior with USB sticks on an OHCI system that
> > work fine elsewhere. The issues aren't consistent, but often when I plug
> > in a device it disconnects when the storage code tries to scan it, then
> > it reconnects, then it disconnects again, ad infinitum. For example:
> >
... snip ...
> >
> > and so on. I have the verbose mass storage output also, but it's a *lot*
> > of output. I could post it somewhere if it would be useful. I've also
> > (rarely) seen USB hubs "thrash" in the same way on this controller, but
> > nowhere near this reproducibly.
> >
> > Any ideas? I do have some reason to suspect the host controller, but if
> > so then I need to track down what the actual issue is, and it's quite
> > reproducible with certain devices.
>
> You should try to track the host controller... it looks like device is
> drawing to much power and it's getting disconnected. Maybe it's a bug
> in controller side.
>
> Can you try this same devices with another linux box ??
>

Yes, they work on another box, although I haven't tried with the same
kernel, but it has failed with multiple kernel versions on the "bad"
system. How could I determine if they're being disconnected for
drawing too much power? I've been considering getting the Aardvark
full-speed passive bus analyzer but I'm not sure that would be
necessary or sufficient.

Mike

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