linux-kernel - [PATCH 3.12 004/142] xhci: fix 10 second timeout on removal of PCI hotpluggable xhci controllers

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Date:   Mon, 10 Apr 2017 17:31:25 +0200
From:   Jiri Slaby <jslaby@...e.cz>
To:     stable@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Mathias Nyman <mathias.nyman@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 004/142] xhci: fix 10 second timeout on removal of PCI hotpluggable xhci controllers

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

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

===============

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@...ux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 drivers/usb/host/xhci-pci.c | 1 +
 drivers/usb/host/xhci.c     | 6 ++++--
 drivers/usb/host/xhci.h     | 1 +
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 6b11f6df76aa..dbde985a5690 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -281,6 +281,7 @@ 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.c b/drivers/usb/host/xhci.c
index 04ba50b05075..f9ca915ac944 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -143,7 +143,8 @@ 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;
 }
@@ -2742,7 +2743,8 @@ 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);
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 83bfb60d19c0..50bfdc61ad8d 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1525,6 +1525,7 @@ 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;
-- 
2.12.2