usb-storage: automatically recognize bad residues

usb-storage: automatically recognize bad residues

commit 59f4ff2ecff4cef36378928cec891785b402e80c upstream

This patch (as1119b) will help to reduce the clutter of usb-storage's
unusual_devs file by automatically detecting some devices that need
the IGNORE_RESIDUE flag.  The idea is that devices should never return
a non-zero residue for an INQUIRY or a READ CAPACITY command unless
they failed to transfer all the requested data.  So if one of these
commands transfers a standard amount of data but there is a positive
residue, we know that the residue is bogus and we can set the flag.

This fixes the problems reported in Bugzilla #11125.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Matthew Frost <artusemrys@sbcglobal.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>