[3.5.yuz,extended,stable] Patch "USB: Enable LPM after a failed probe." has been added to staging queue

Message ID 1353474498-8152-1-git-send-email-herton.krzesinski@canonical.com
State New
Headers show

Commit Message

Herton Ronaldo Krzesinski Nov. 21, 2012, 5:08 a.m.
This is a note to let you know that I have just added a patch titled

    USB: Enable LPM after a failed probe.

to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree 
which can be found at:


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

For more information about the 3.5.yuz tree, see



From b4a1fc226724e17594b7bc855ff415d8db3e0d83 Mon Sep 17 00:00:00 2001
From: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Date: Thu, 4 Oct 2012 09:53:43 -0700
Subject: [PATCH] USB: Enable LPM after a failed probe.

commit d01f87c0ffa96cb44faa78710711eb6e974b891c upstream.

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>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
 drivers/usb/core/driver.c |    4 ++++
 1 file changed, 4 insertions(+)



diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index f536aeb..da33079 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -371,6 +371,10 @@  static int usb_probe_interface(struct device *dev)
 	intf->condition = USB_INTERFACE_UNBOUND;

+	/* 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 */
 	if (driver->supports_autosuspend)