option to ignore flash memory device at USB1.1 "full" speed

Adam Williamson awilliam at redhat.com
Tue Jun 18 08:00:39 UTC 2013

On Tue, 2013-06-18 at 08:26 +0200, Hans de Goede wrote:
> Hi,
> On 06/17/2013 10:37 PM, Adam Williamson wrote:
> > On Sun, 2013-06-16 at 22:33 +0100, Matthew Garrett wrote:
> >> On Sun, Jun 16, 2013 at 10:11:42PM +0100, David Woodhouse wrote:
> >>> On Sun, 2013-06-16 at 05:38 +0100, Matthew Garrett wrote:
> >>>> On Sat, Jun 15, 2013 at 08:24:33AM -0700, John Reiser wrote:
> >>>>> How can I force the system not to recognize a USB2.0 flash memory
> >>>> device at USB1.1 speed?
> >>>>
> >>>> You can't - it's negotiated at the host controller level, the OS isn't
> >>>> involved.
> >>>
> >>> You can't force it to use USB2 mode when for some reason it's negotiated
> >>> something slower. But you can *detect* that it's connected as a USB1
> >>> device and refuse to mount it, surely? And then the user will unplug it
> >>> and plug it in again, until it works correctly.
> >>
> >> Yeah, I guess you could write a udev rule that detected that case and
> >> flagged it such that it didn't get automounted.
> >
> > IIRC, Windows pops up one of its little yellow warnings associated with
> > a notification tray icon when this happens - the medium is mounted but
> > you get a warning that it's running at a slow speed. That seems
> > reasonable.
> And IIRC the kernel will log a message when plugging a usb-2 device into
> a port which is not usb-2 capable. But if I understand correctly, that is
> not the issue here?

Oh yeah, that might be the Windows warning I'm remembering.

> The issue seems to be that sometimes a usb-2 device connects at usb-1 speed
> even though plugged into a usb-2 port, right ?

AIUI, yes.

> That is just buggy hardware, and I don't think that warrants any special
> handling. I would try cleaning the contacts of both the usb-port and
> the usb-stick. Also if a usb-extension cable is involved, try replacing it,
> or taking it out of the loop all-together.

Well, yes, those are all perfectly sensible steps: I think the idea of
the OP was to alert people that this was happening precisely so they
could take the sensible debugging steps :)
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Twitter: AdamW_Fedora | identi.ca: adamwfedora

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