[PATCH 3/5] xhci: Add rmb() between reading event validity & event data access.

[Matt Evans]

On weakly-ordered systems, the reading of an event's content must occur
after reading the event's validity.

Signed-off-by: Matt Evans <matt at ozlabs.org>
---
 drivers/usb/host/xhci-ring.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 45f3b77..b46efd9 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2151,7 +2151,7 @@ static void xhci_handle_event(struct xhci_hcd *xhci)
 		return;
 	}
 	xhci_dbg(xhci, "%s - OS owns TRB\n", __func__);
-
+	rmb();
 	/* FIXME: Handle more event types. */
 	switch ((le32_to_cpu(event->event_cmd.flags) & TRB_TYPE_BITMASK)) {
 	case TRB_TYPE(TRB_COMPLETION):
-- 
1.7.0.4