diff options
author | Alan Stern <stern@rowland.harvard.edu> | 2014-07-18 00:34:29 +0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-07-18 04:05:07 +0400 |
commit | 977dcfdc60311e7aa571cabf6f39c36dde13339e (patch) | |
tree | bb095c9bce743969f99fc368aaeeac4c498042e4 | |
parent | 256dbcd80f1ccf8abf421c1d72ba79a4e29941dd (diff) | |
download | linux-977dcfdc60311e7aa571cabf6f39c36dde13339e.tar.xz |
USB: OHCI: don't lose track of EDs when a controller dies
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>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | drivers/usb/host/ohci-q.c | 46 |
1 files changed, 29 insertions, 17 deletions
diff --git a/drivers/usb/host/ohci-q.c b/drivers/usb/host/ohci-q.c index 517d04d5c150..a6376f3e55cb 100644 --- a/drivers/usb/host/ohci-q.c +++ b/drivers/usb/host/ohci-q.c @@ -311,8 +311,7 @@ static void periodic_unlink (struct ohci_hcd *ohci, struct ed *ed) * - ED_OPER: when there's any request queued, the ED gets rescheduled * immediately. HC should be working on them. * - * - ED_IDLE: when there's no TD queue. there's no reason for the HC - * to care about this ED; safe to disable the endpoint. + * - ED_IDLE: when there's no TD queue or the HC isn't running. * * When finish_unlinks() runs later, after SOF interrupt, it will often * complete one or more URB unlinks before making that state change. @@ -954,6 +953,10 @@ rescan_all: int completed, modified; __hc32 *prev; + /* Is this ED already invisible to the hardware? */ + if (ed->state == ED_IDLE) + goto ed_idle; + /* only take off EDs that the HC isn't using, accounting for * frame counter wraps and EDs with partially retired TDs */ @@ -983,12 +986,20 @@ skip_ed: } } + /* ED's now officially unlinked, hc doesn't see */ + ed->state = ED_IDLE; + if (quirk_zfmicro(ohci) && ed->type == PIPE_INTERRUPT) + ohci->eds_scheduled--; + ed->hwHeadP &= ~cpu_to_hc32(ohci, ED_H); + ed->hwNextED = 0; + wmb(); + ed->hwINFO &= ~cpu_to_hc32(ohci, ED_SKIP | ED_DEQUEUE); +ed_idle: + /* reentrancy: if we drop the schedule lock, someone might * have modified this list. normally it's just prepending * entries (which we'd ignore), but paranoia won't hurt. */ - *last = ed->ed_next; - ed->ed_next = NULL; modified = 0; /* unlink urbs as requested, but rescan the list after @@ -1046,19 +1057,20 @@ rescan_this: if (completed && !list_empty (&ed->td_list)) goto rescan_this; - /* ED's now officially unlinked, hc doesn't see */ - ed->state = ED_IDLE; - if (quirk_zfmicro(ohci) && ed->type == PIPE_INTERRUPT) - ohci->eds_scheduled--; - ed->hwHeadP &= ~cpu_to_hc32(ohci, ED_H); - ed->hwNextED = 0; - wmb (); - ed->hwINFO &= ~cpu_to_hc32 (ohci, ED_SKIP | ED_DEQUEUE); - - /* but if there's work queued, reschedule */ - if (!list_empty (&ed->td_list)) { - if (ohci->rh_state == OHCI_RH_RUNNING) - ed_schedule (ohci, ed); + /* + * If no TDs are queued, take ED off the ed_rm_list. + * Otherwise, if the HC is running, reschedule. + * If not, leave it on the list for further dequeues. + */ + if (list_empty(&ed->td_list)) { + *last = ed->ed_next; + ed->ed_next = NULL; + } else if (ohci->rh_state == OHCI_RH_RUNNING) { + *last = ed->ed_next; + ed->ed_next = NULL; + ed_schedule(ohci, ed); + } else { + last = &ed->ed_next; } if (modified) |