[3.13.y-ckt stable] Patch "xhci: prevent bus_suspend if SS port resuming in phase 1" has been added to staging queue

Kamal Mostafa kamal at canonical.com
Wed Sep 2 00:55:25 UTC 2015


This is a note to let you know that I have just added a patch titled

    xhci: prevent bus_suspend if SS port resuming in phase 1

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt26.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 4fcc75c7b72b90aa407384237add8f155f1bde81 Mon Sep 17 00:00:00 2001
From: Zhuang Jin Can <jin.can.zhuang at intel.com>
Date: Tue, 21 Jul 2015 17:20:30 +0300
Subject: xhci: prevent bus_suspend if SS port resuming in phase 1

commit fac4271d1126c45ceaceb7f4a336317b771eb121 upstream.

When the link is just waken, it's in Resume state, and driver sets PLS to
U0. This refers to Phase 1. Phase 2 refers to when the link has completed
the transition from Resume state to U0.

With the fix of xhci: report U3 when link is in resume state, it also
exposes an issue that usb3 roothub and controller can suspend right
after phase 1, and this causes a hard hang in controller.

To fix the issue, we need to prevent usb3 bus suspend if any port is
resuming in phase 1.

[merge separate USB2 and USB3 port resume checking to one -Mathias]
Signed-off-by: Zhuang Jin Can <jin.can.zhuang at intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman at linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/host/xhci-hub.c  | 6 +++---
 drivers/usb/host/xhci-ring.c | 3 +++
 drivers/usb/host/xhci.h      | 1 +
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index d2d82de..672e0b1 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -1121,10 +1121,10 @@ int xhci_bus_suspend(struct usb_hcd *hcd)
 	spin_lock_irqsave(&xhci->lock, flags);

 	if (hcd->self.root_hub->do_remote_wakeup) {
-		if (bus_state->resuming_ports) {
+		if (bus_state->resuming_ports ||	/* USB2 */
+		    bus_state->port_remote_wakeup) {	/* USB3 */
 			spin_unlock_irqrestore(&xhci->lock, flags);
-			xhci_dbg(xhci, "suspend failed because "
-						"a port is resuming\n");
+			xhci_dbg(xhci, "suspend failed because a port is resuming\n");
 			return -EBUSY;
 		}
 	}
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index d328d16..3f1276c 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1757,6 +1757,9 @@ static void handle_port_status(struct xhci_hcd *xhci,
 		usb_hcd_resume_root_hub(hcd);
 	}

+	if (hcd->speed == HCD_USB3 && (temp & PORT_PLS_MASK) == XDEV_INACTIVE)
+		bus_state->port_remote_wakeup &= ~(1 << faked_port_index);
+
 	if ((temp & PORT_PLC) && (temp & PORT_PLS_MASK) == XDEV_RESUME) {
 		xhci_dbg(xhci, "port resume event for port %d\n", port_id);

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 5b77371..d053de1 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -285,6 +285,7 @@ struct xhci_op_regs {
 #define XDEV_U0		(0x0 << 5)
 #define XDEV_U2		(0x2 << 5)
 #define XDEV_U3		(0x3 << 5)
+#define XDEV_INACTIVE	(0x6 << 5)
 #define XDEV_RESUME	(0xf << 5)
 /* true: port has power (see HCC_PPC) */
 #define PORT_POWER	(1 << 9)
--
1.9.1





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