tree 58e4835774c03c8e95d129c854c8d408b9f82521
parent 0f312efc84c9f3f95d77b5b291d4d0ba24042272
author Alan Stern <stern@rowland.harvard.edu> 1405629269 -0400
committer Matthias Kaehlcke <mka@google.com> 1433366108 -0700

USB: OHCI: don't lose track of EDs when a controller dies

commit 977dcfdc60311e7aa571cabf6f39c36dde13339e upstream.

This patch fixes a bug in ohci-hcd.  When an URB is unlinked, the
corresponding Endpoint Descriptor is added to the ed_rm_list and taken
off the hardware schedule.  Once the ED is no longer visible to the
hardware, finish_unlinks() handles the URBs that were unlinked or have
completed.  If any URBs remain attached to the ED, the ED is added
back to the hardware schedule -- but only if the controller is
running.

This fails when a controller dies.  A non-empty ED does not get added
back to the hardware schedule and does not remain on the ed_rm_list;
ohci-hcd loses track of it.  The remaining URBs cannot be unlinked,
which causes the USB stack to hang.

The patch changes finish_unlinks() so that non-empty EDs remain on
the ed_rm_list if the controller isn't running.  This requires moving
some of the existing code around, to avoid modifying the ED's hardware
fields more than once.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: keep using HC_IS_RUNNING()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>