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authorAlan Stern <stern@rowland.harvard.edu>2011-04-05 13:36:15 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2011-04-13 15:44:02 -0700
commit94ae4976e253757e9b03a44d27d41b20f1829d80 (patch)
tree4ef5bdb65b1c968716fc7dc523bdd209b53793b4 /drivers
parent505d1f69ec4f8697a74711fb3a01ed151fda3834 (diff)
USB: EHCI: unlink unused QHs when the controller is stopped
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> CC: <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
-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 98ded66e8d3f..42abd0f603bf 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -1247,24 +1247,27 @@ 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;
@@ -1285,9 +1288,9 @@ 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;

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