[patch 20/32] USB: EHCI: expedite unlinks when the root hub is suspended

[Greg KH]

2.6.27-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>

commit 391016f6e2fe3b9979b4c6880a76e5e434d6947c upstream.

This patch (as1225) fixes a bug in ehci-hcd.  The condition for
whether unlinked QHs can become IDLE should not be that the controller
is halted, but rather that the controller isn't running.  In other
words when the root hub is suspended, the hardware doesn't own any
QHs.

This fixes a problem that can show up during hibernation: If a QH is
only partially unlinked when the root hub is frozen, then when the
root hub is thawed the QH won't be in the IDLE state.  As a result it
can't be used properly for new URB submissions.

Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Reported-by: Brandon Philips <brandon@xxxxxxxx>
Tested-by: Brandon Philips <brandon@xxxxxxxx>
Acked-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/usb/host/ehci-q.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -1095,7 +1095,8 @@ static void start_unlink_async (struct e
 	prev->qh_next = qh->qh_next;
 	wmb ();
 
-	if (unlikely (ehci_to_hcd(ehci)->state == HC_STATE_HALT)) {
+	/* If the controller isn't running, we don't have to wait for it */
+	if (unlikely(!HC_IS_RUNNING(ehci_to_hcd(ehci)->state))) {
 		/* if (unlikely (qh->reclaim != 0))
 		 *	this will recurse, probably not much
 		 */


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