[3.13.y.z extended stable] Patch "xhci: Prevent runtime pm from autosuspending during initialization" has been added to staging queue

Kamal Mostafa kamal at canonical.com
Thu May 1 19:17:10 UTC 2014

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

    xhci: Prevent runtime pm from autosuspending during initialization

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


This patch is scheduled to be released in version

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.z tree, see



>From 8df4a3019be582d149a83315ad99482b56a833b6 Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman at linux.intel.com>
Date: Mon, 3 Mar 2014 19:30:17 +0200
Subject: xhci: Prevent runtime pm from autosuspending during initialization
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit bcffae7708eb8352f44dc510b326541fe43a02a4 upstream.

xHCI driver has its own pci probe function that will call usb_hcd_pci_probe
to register its usb-2 bus, and then continue to manually register the
usb-3 bus. usb_hcd_pci_probe does a pm_runtime_put_noidle at the end and
might thus trigger a runtime suspend before the usb-3 bus is ready.

Prevent the runtime suspend by increasing the usage count in the
beginning of xhci_pci_probe, and decrease it once the usb-3 bus is

xhci-platform driver is not using usb_hcd_pci_probe to set up
busses and should not need to have it's usage count increased during probe.

Signed-off-by: Mathias Nyman <mathias.nyman at linux.intel.com>
Acked-by: Dan Williams <dan.j.williams at intel.com>
Acked-by: Alan Stern <stern at rowland.harvard.edu>
Signed-off-by: Sarah Sharp <sarah.a.sharp at linux.intel.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
 drivers/usb/host/xhci-pci.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index 1af67a2..d069224 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -190,6 +190,10 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	struct usb_hcd *hcd;

 	driver = (struct hc_driver *)id->driver_data;
+	/* Prevent runtime suspending between USB-2 and USB-3 initialization */
+	pm_runtime_get_noresume(&dev->dev);
 	/* Register the USB 2.0 roothub.
 	 * FIXME: USB core must know to register the USB 2.0 roothub first.
 	 * This is sort of silly, because we could just set the HCD driver flags
@@ -199,7 +203,7 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	retval = usb_hcd_pci_probe(dev, id);

 	if (retval)
-		return retval;
+		goto put_runtime_pm;

 	/* USB 2.0 roothub is stored in the PCI device now. */
 	hcd = dev_get_drvdata(&dev->dev);
@@ -228,12 +232,17 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	if (xhci->quirks & XHCI_LPM_SUPPORT)
 		hcd_to_bus(xhci->shared_hcd)->root_hub->lpm_capable = 1;

+	/* USB-2 and USB-3 roothubs initialized, allow runtime pm suspend */
+	pm_runtime_put_noidle(&dev->dev);
 	return 0;

+	pm_runtime_put_noidle(&dev->dev);
 	return retval;


More information about the kernel-team mailing list