[PATCH 4.9 13/48] xhci: Identify USB 3.1 capable hosts by their port protocol capability

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>

commit ea7d0d69426cab6747ed311c53f4142eb48b9454 upstream.

Many USB 3.1 capable hosts never updated the Serial Bus Release Number
(SBRN) register to USB 3.1 from USB 3.0

xhci driver identified USB 3.1 capable hosts based on this SBRN register,
which according to specs "contains the release of the Universal Serial
Bus Specification with which this Universal Serial Bus Host Controller
module is compliant." but still in october 2017 gives USB 3.0 as
the only possible option.

Make an additional check for USB 3.1 support and enable it if the xHCI
supported protocol capablity lists USB 3.1 capable ports.

Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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

--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4855,7 +4855,8 @@ int xhci_gen_setup(struct usb_hcd *hcd,
 		 */
 		hcd->has_tt = 1;
 	} else {
-		if (xhci->sbrn == 0x31) {
+		/* Some 3.1 hosts return sbrn 0x30, can't rely on sbrn alone */
+		if (xhci->sbrn == 0x31 || xhci->usb3_rhub.min_rev >= 1) {
 			xhci_info(xhci, "Host supports USB 3.1 Enhanced SuperSpeed\n");
 			hcd->speed = HCD_USB31;
 			hcd->self.root_hub->speed = USB_SPEED_SUPER_PLUS;