Re: Problems accessing USB Mass Storage

Patrick Mansfield
2002-09-17T22:16:37Z

On Tue, Sep 17, 2002 at 05:04:19PM -0500, Thomas Dodd wrote:
>
>
> Rogier Wolff wrote:
> > On Tue, Sep 17, 2002 at 10:46:31AM -0700, Greg KH wrote:
> >
> >>On Tue, Sep 17, 2002 at 12:37:37PM -0500, Thomas Dodd wrote:
> >>
> >>>I get the feeling it's not a true mass storage device.
> >>
> >>Sounds like it.
> >
> >
> > Nope. Sure does sound like it's a mass storage device. And it works
> > too.
> >
> > The kernel managed to read the partition table off it, and got
> > one valid partition: sda1.
>
> Accept that you cannot read data from the device. At all.
> Even dd fails. And the windows drivers work (using XP
> in vmware it think it was) correctly on this same device.
>
> -Thomas

But it did read the first 8 blocks off the devices when it
read the partition, the usb debug showed:

usb-storage: Command READ_10 (10 bytes)
usb-storage: 28 00 00 00 00 00 00 00 08 00 30 da

With offsets starting at 0 -

Bytes 2 - 5 are the logical block address, all 0.
Bytes 7 - 8 are the transfer length - 8 blocks.

The last two bytes are junk.

You should be able to run the equivalent:

dd if=/dev/sda of=/dev/zero bs=512 count=8

And, look in dmesg for the failure message of the first read that fails, it
could have set the device offline.

-- Patrick Mansfield