[4.2.y-ckt stable] Patch "xhci: fix 10 second timeout on removal of PCI hotpluggable xhci controllers" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

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

    xhci: fix 10 second timeout on removal of PCI hotpluggable xhci controllers

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt9.

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

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From d2f5dea2861657a776ef81bf69d69d641f9dc510 Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman at linux.intel.com>
Date: Fri, 8 Apr 2016 16:25:10 +0300
Subject: xhci: fix 10 second timeout on removal of PCI hotpluggable xhci
 controllers

commit 98d74f9ceaefc2b6c4a6440050163a83be0abede upstream.

PCI hotpluggable xhci controllers such as some Alpine Ridge solutions will
remove the xhci controller from the PCI bus when the last USB device is
disconnected.

Add a flag to indicate that the host is being removed to avoid queueing
configure_endpoint commands for the dropped endpoints.
For PCI hotplugged controllers this will prevent 5 second command timeouts
For static xhci controllers the configure_endpoint command is not needed
in the removal case as everything will be returned, freed, and the
controller is reset.

For now the flag is only set for PCI connected host controllers.

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-pci.c  | 1 +
 drivers/usb/host/xhci-ring.c | 3 ++-
 drivers/usb/host/xhci.c      | 8 +++++---
 drivers/usb/host/xhci.h      | 1 +
 4 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 08fb12f..6494798 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -303,6 +303,7 @@ static void xhci_pci_remove(struct pci_dev *dev)
 	struct xhci_hcd *xhci;

 	xhci = hcd_to_xhci(pci_get_drvdata(dev));
+	xhci->xhc_state |= XHCI_STATE_REMOVING;
 	if (xhci->shared_hcd) {
 		usb_remove_hcd(xhci->shared_hcd);
 		usb_put_hcd(xhci->shared_hcd);
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index ea9690e..c7fe14b 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3843,7 +3843,8 @@ static int queue_command(struct xhci_hcd *xhci, struct xhci_command *cmd,
 	int reserved_trbs = xhci->cmd_ring_reserved_trbs;
 	int ret;

-	if (xhci->xhc_state) {
+	if ((xhci->xhc_state & XHCI_STATE_DYING) ||
+		(xhci->xhc_state & XHCI_STATE_HALTED)) {
 		xhci_dbg(xhci, "xHCI dying or halted, can't queue_command\n");
 		return -ESHUTDOWN;
 	}
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 21f638d..c718b22 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -146,7 +146,8 @@ static int xhci_start(struct xhci_hcd *xhci)
 				"waited %u microseconds.\n",
 				XHCI_MAX_HALT_USEC);
 	if (!ret)
-		xhci->xhc_state &= ~(XHCI_STATE_HALTED | XHCI_STATE_DYING);
+		/* clear state flags. Including dying, halted or removing */
+		xhci->xhc_state = 0;

 	return ret;
 }
@@ -2753,7 +2754,8 @@ int xhci_check_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
 	if (ret <= 0)
 		return ret;
 	xhci = hcd_to_xhci(hcd);
-	if (xhci->xhc_state & XHCI_STATE_DYING)
+	if ((xhci->xhc_state & XHCI_STATE_DYING) ||
+		(xhci->xhc_state & XHCI_STATE_REMOVING))
 		return -ENODEV;

 	xhci_dbg(xhci, "%s called for udev %p\n", __func__, udev);
@@ -3800,7 +3802,7 @@ static int xhci_setup_device(struct usb_hcd *hcd, struct usb_device *udev,

 	mutex_lock(&xhci->mutex);

-	if (xhci->xhc_state)	/* dying or halted */
+	if (xhci->xhc_state)	/* dying, removing or halted */
 		goto out;

 	if (!udev->slot_id) {
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 82be4b5..79b95de 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1534,6 +1534,7 @@ struct xhci_hcd {
  */
 #define XHCI_STATE_DYING	(1 << 0)
 #define XHCI_STATE_HALTED	(1 << 1)
+#define XHCI_STATE_REMOVING	(1 << 2)
 	/* Statistics */
 	int			error_bitmask;
 	unsigned int		quirks;
--
2.7.4