This is a note to let you know that I've just added the patch titled
USB: EHCI: unlink unused QHs when the controller is stopped
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also will be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 94ae4976e253757e9b03a44d27d41b20f1829d80 Mon Sep 17 00:00:00 2001
From: Alan Stern <[email protected]>
Date: Tue, 5 Apr 2011 13:36:15 -0400
Subject: 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 <[email protected]>
Reported-and-Tested-by: Dan Duval <[email protected]>
CC: <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/usb/host/ehci-q.c | 15 +++++++++------
1 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index 98ded66..42abd0f 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;
--
1.7.4.2
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