3.16.63-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Aaron Ma <aaron...@canonical.com>

commit 958c0bd86075d4ef1c936998deefe1947e539240 upstream.

Realtek USB3.0 Card Reader [0bda:0328] reports wrong port status on
Cannon lake PCH USB3.1 xHCI [8086:a36d] after resume from S3,
after clear port reset it works fine.

Since this device is registered on USB3 roothub at boot,
when port status reports not superspeed, xhci_get_port_status will call
an uninitialized completion in bus_state[0].
Kernel will hang because of NULL pointer.

Restrict the USB2 resume status check in USB2 roothub to fix hang issue.

Signed-off-by: Aaron Ma <aaron...@canonical.com>
Signed-off-by: Mathias Nyman <mathias.ny...@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
 drivers/usb/host/xhci-hub.c  | 2 +-
 drivers/usb/host/xhci-ring.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -620,7 +620,7 @@ static u32 xhci_get_port_status(struct u
                        status |= USB_PORT_STAT_SUSPEND;
        }
        if ((raw_port_status & PORT_PLS_MASK) == XDEV_RESUME &&
-                       !DEV_SUPERSPEED(raw_port_status)) {
+               !DEV_SUPERSPEED(raw_port_status) && hcd->speed < HCD_USB3) {
                if ((raw_port_status & PORT_RESET) ||
                                !(raw_port_status & PORT_PE))
                        return 0xffffffff;
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1676,7 +1676,7 @@ static void handle_port_status(struct xh
         * RExit to a disconnect state).  If so, let the the driver know it's
         * out of the RExit state.
         */
-       if (!DEV_SUPERSPEED(temp) &&
+       if (!DEV_SUPERSPEED(temp) && hcd->speed < HCD_USB3 &&
                        test_and_clear_bit(faked_port_index,
                                &bus_state->rexit_ports)) {
                complete(&bus_state->rexit_done[faked_port_index]);

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