tree a4be2521cf03591dd220156f4f0a92f3c49f4f89
parent 056761e55c8687ddf3db14226213f2e8dc2689bc
author David Brownell <dbrownell@users.sourceforge.net> 1213426794 -0700
committer Greg Kroah-Hartman <gregkh@suse.de> 1215134436 -0700

USB: ohci - record data toggle after unlink

This patch fixes a problem with OHCI where canceling bulk or
interrupt URBs may lose track of the right data toggle.  This
seems to be a longstanding bug, possibly dating back to the
Linux 2.4 kernel, which stayed hidden because

 (a) about half the time the data toggle bit was correct;
 (b) canceling such URBs is unusual; and
 (c) the few drivers which cancel these URBs either
      [1] do it only as part of shutting down, or
      [2] have fault recovery logic, which recovers.

For those transfer types, the toggle is normally written back
into the ED when each TD is retired.  But canceling bypasses
the mechanism used to retire TDs ... so on average, half the
time the toggle bit will be invalid after cancelation.

The fix is simple:  the toggle state of any canceled TDs are
propagated back to the ED in the finish_unlinks function.

(Issue found by leonidv11@gmail.com ...)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Leonid <leonidv11@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>