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USB: Enable LPM after a failed probe.

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Before a driver is probed, we want to disable USB 3.0 Link Power
Management (LPM), in case the driver needs hub-initiated LPM disabled.
After the probe finishes, we want to attempt to re-enable LPM, order to
balance the LPM ref count.

When a probe fails (such as when libusual doesn't want to bind to a USB
3.0 mass storage device), make sure to balance the LPM ref counts by
re-enabling LPM.

This patch should be backported to kernels as old as 3.5, that contain
the commit 8306095fd2c1100e8244c09bf560f97aca5a311d "USB: Disable USB
3.0 LPM in critical sections."

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org
This commit is contained in:
Sarah Sharp 2012-10-04 09:53:43 -07:00
parent ecefbd94b8
commit d01f87c0ff
1 changed files with 4 additions and 0 deletions
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4
drivers/usb/core/driver.c
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@ -367,6 +367,10 @@ static int usb_probe_interface(struct device *dev)
intf->condition = USB_INTERFACE_UNBOUND; intf->condition = USB_INTERFACE_UNBOUND;
usb_cancel_queued_reset(intf); usb_cancel_queued_reset(intf);
/* If the LPM disable succeeded, balance the ref counts. */
if (!lpm_disable_error)
usb_unlocked_enable_lpm(udev);
/* Unbound interfaces are always runtime-PM-disabled and -suspended */ /* Unbound interfaces are always runtime-PM-disabled and -suspended */
if (driver->supports_autosuspend) if (driver->supports_autosuspend)
pm_runtime_disable(dev); pm_runtime_disable(dev);