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?
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 ?
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.
I've seen similar issue in the past and sofar it has always been bad hardware.
Sometimes things like cleaning contacts help, sometimes the contacts on the
usb-port side are simply worn out / too loose.
Regards,
Hans
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