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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Mathias Nyman <mathias.nyman@linux.intel.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.16 084/161] xhci: Show what USB release number the xHC supports from protocol capablity
Date:   Thu, 24 May 2018 11:38:29 +0200
Message-Id: <20180524093028.551719646@linuxfoundation.org>
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4.16-stable review patch.  If anyone has any objections, please let me know.

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

From: Mathias Nyman <mathias.nyman@linux.intel.com>

[ Upstream commit 0ee78c101425aae681c631ba59c6ac7f44b1d83a ]

xhci driver displays the supported xHC USB revision in a message during
driver load:

"Host supports USB 3.1 Enhanced SuperSpeed"

Get the USB minor revision number from the xhci protocol capability.
This will show the correct supported revisions for new USB 3.2 and later
hosts

Don't rely on the SBRN (serial bus revision number) register, it's often
showing 0x30 (USB3.0) for hosts that support USB 3.1

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/host/xhci.c |   14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -4769,6 +4769,7 @@ int xhci_gen_setup(struct usb_hcd *hcd,
 	 * quirks
 	 */
 	struct device		*dev = hcd->self.sysdev;
+	unsigned int		minor_rev;
 	int			retval;
 
 	/* Accept arbitrarily long scatter-gather lists */
@@ -4796,12 +4797,19 @@ int xhci_gen_setup(struct usb_hcd *hcd,
 		 */
 		hcd->has_tt = 1;
 	} else {
-		/* 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");
+		/*
+		 * Some 3.1 hosts return sbrn 0x30, use xhci supported protocol
+		 * minor revision instead of sbrn
+		 */
+		minor_rev = xhci->usb3_rhub.min_rev;
+		if (minor_rev) {
 			hcd->speed = HCD_USB31;
 			hcd->self.root_hub->speed = USB_SPEED_SUPER_PLUS;
 		}
+		xhci_info(xhci, "Host supports USB 3.%x %s SuperSpeed\n",
+			  minor_rev,
+			  minor_rev ? "Enhanced" : "");
+
 		/* xHCI private pointer was set in xhci_pci_probe for the second
 		 * registered roothub.
 		 */