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authorAlan Stern <stern@rowland.harvard.edu>2011-04-05 13:36:15 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2011-04-22 08:50:03 -0700
commit603c383fb3d20b1657cdae22b6b4397d1debe190 (patch)
treefd5c64e4542e477bc8dc9d95e5a50dffc20c2f3a
parent968b9098cac22e2a05f27a334067c9bb75121bd9 (diff)
downloadlinux-linaro-stable-603c383fb3d20b1657cdae22b6b4397d1debe190.tar.gz
USB: EHCI: unlink unused QHs when the controller is stopped
commit 94ae4976e253757e9b03a44d27d41b20f1829d80 upstream. This patch (as1458) fixes a problem affecting ultra-reliable systems: When hardware failover of an EHCI controller occurs, the data structures do not get released correctly. This is because the routine responsible for removing unused QHs from the async schedule assumes the controller is running properly (the frame counter is used in determining how long the QH has been idle) -- but when a failover causes the controller to be electronically disconnected from the PCI bus, obviously it stops running. The solution is simple: Allow scan_async() to remove a QH from the async schedule if it has been idle for long enough _or_ if the controller is stopped. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-and-Tested-by: Dan Duval <dan.duval@stratus.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/usb/host/ehci-q.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index d1d4bb10779c..781c573af2e5 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -1246,24 +1246,27 @@ static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
static void scan_async (struct ehci_hcd *ehci)
{
+ bool stopped;
struct ehci_qh *qh;
enum ehci_timer_action action = TIMER_IO_WATCHDOG;
ehci->stamp = ehci_readl(ehci, &ehci->regs->frame_index);
timer_action_done (ehci, TIMER_ASYNC_SHRINK);
rescan:
+ stopped = !HC_IS_RUNNING(ehci_to_hcd(ehci)->state);
qh = ehci->async->qh_next.qh;
if (likely (qh != NULL)) {
do {
/* clean any finished work for this qh */
- if (!list_empty (&qh->qtd_list)
- && qh->stamp != ehci->stamp) {
+ if (!list_empty(&qh->qtd_list) && (stopped ||
+ qh->stamp != ehci->stamp)) {
int temp;
/* unlinks could happen here; completion
* reporting drops the lock. rescan using
* the latest schedule, but don't rescan
- * qhs we already finished (no looping).
+ * qhs we already finished (no looping)
+ * unless the controller is stopped.
*/
qh = qh_get (qh);
qh->stamp = ehci->stamp;
@@ -1284,9 +1287,9 @@ rescan:
*/
if (list_empty(&qh->qtd_list)
&& qh->qh_state == QH_STATE_LINKED) {
- if (!ehci->reclaim
- && ((ehci->stamp - qh->stamp) & 0x1fff)
- >= (EHCI_SHRINK_FRAMES * 8))
+ if (!ehci->reclaim && (stopped ||
+ ((ehci->stamp - qh->stamp) & 0x1fff)
+ >= EHCI_SHRINK_FRAMES * 8))
start_unlink_async(ehci, qh);
else
action = TIMER_ASYNC_SHRINK;