[PATCH 3.12 083/182] xhci: Prevent runtime pm from autosuspending during initialization

Jiri Slaby
2014-05-13T09:44:47Z

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

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

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

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
ready.

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@linux.intel.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
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 1af67a214d33..d06922469000 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;

put_usb3_hcd:
usb_put_hcd(xhci->shared_hcd);
dealloc_usb2_hcd:
usb_hcd_pci_remove(dev);
+put_runtime_pm:
+ pm_runtime_put_noidle(&dev->dev);
return retval;
}

--
1.9.3