USB: convert to the runtime PM framework

This patch (as1329) converts the USB stack over to the PM core's
runtime PM framework.  This involves numerous changes throughout
usbcore, especially to hub.c and driver.c.  Perhaps the most notable
change is that CONFIG_USB_SUSPEND now depends on CONFIG_PM_RUNTIME
instead of CONFIG_PM.

Several fields in the usb_device and usb_interface structures are no
longer needed.  Some code which used to depend on CONFIG_USB_PM now
depends on CONFIG_USB_SUSPEND (requiring some rearrangement of header
files).

The only visible change in behavior should be that following a system
sleep (resume from RAM or resume from hibernation), autosuspended USB
devices will be resumed just like everything else.  They won't remain
suspended.  But if they aren't in use then they will naturally
autosuspend again in a few seconds.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

11 files changed, 490 insertions, 784 deletions

diff --git a/Documentation/usb/power-management.txt b/Documentation/usb/power-management.txt
index e3fa189c257..2790ad48cfc 100644
--- a/Documentation/usb/power-management.txt
+++ b/Documentation/usb/power-management.txt
@@ -2,7 +2,7 @@
 
 		 Alan Stern <stern@rowland.harvard.edu>
 
-			    November 10, 2009
+			    December 11, 2009
 
 
 
@@ -29,9 +29,9 @@ covered to some extent (see Documentation/power/*.txt for more
 information about system PM).
 
 Note: Dynamic PM support for USB is present only if the kernel was
-built with CONFIG_USB_SUSPEND enabled.  System PM support is present
-only if the kernel was built with CONFIG_SUSPEND or CONFIG_HIBERNATION
-enabled.
+built with CONFIG_USB_SUSPEND enabled (which depends on
+CONFIG_PM_RUNTIME).  System PM support is present only if the kernel
+was built with CONFIG_SUSPEND or CONFIG_HIBERNATION enabled.
 
 
 	What is Remote Wakeup?
@@ -326,64 +326,63 @@ driver does so by calling these six functions:
 	void usb_autopm_get_interface_no_resume(struct usb_interface *intf);
 	void usb_autopm_put_interface_no_suspend(struct usb_interface *intf);
 
-The functions work by maintaining a counter in the usb_interface
-structure.  When intf->pm_usage_count is > 0 then the interface is
-deemed to be busy, and the kernel will not autosuspend the interface's
-device.  When intf->pm_usage_count is <= 0 then the interface is
-considered to be idle, and the kernel may autosuspend the device.
+The functions work by maintaining a usage counter in the
+usb_interface's embedded device structure.  When the counter is > 0
+then the interface is deemed to be busy, and the kernel will not
+autosuspend the interface's device.  When the usage counter is = 0
+then the interface is considered to be idle, and the kernel may
+autosuspend the device.
 
-(There is a similar pm_usage_count field in struct usb_device,
+(There is a similar usage counter field in struct usb_device,
 associated with the device itself rather than any of its interfaces.
-This field is used only by the USB core.)
-
-Drivers must not modify intf->pm_usage_count directly; its value
-should be changed only be using the functions listed above.  Drivers
-are responsible for insuring that the overall change to pm_usage_count
-during their lifetime balances out to 0 (it may be necessary for the
-disconnect method to call usb_autopm_put_interface() one or more times
-to fulfill this requirement).  The first two routines use the PM mutex
-in struct usb_device for mutual exclusion; drivers using the async
-routines are responsible for their own synchronization and mutual
-exclusion.
-
-	usb_autopm_get_interface() increments pm_usage_count and
-	attempts an autoresume if the new value is > 0 and the
-	device is suspended.
-
-	usb_autopm_put_interface() decrements pm_usage_count and
-	attempts an autosuspend if the new value is <= 0 and the
-	device isn't suspended.
+This counter is used only by the USB core.)
+
+Drivers need not be concerned about balancing changes to the usage
+counter; the USB core will undo any remaining "get"s when a driver
+is unbound from its interface.  As a corollary, drivers must not call
+any of the usb_autopm_* functions after their diconnect() routine has
+returned.
+
+Drivers using the async routines are responsible for their own
+synchronization and mutual exclusion.
+
+	usb_autopm_get_interface() increments the usage counter and
+	does an autoresume if the device is suspended.  If the
+	autoresume fails, the counter is decremented back.
+
+	usb_autopm_put_interface() decrements the usage counter and
+	attempts an autosuspend if the new value is = 0.
 
 	usb_autopm_get_interface_async() and
 	usb_autopm_put_interface_async() do almost the same things as
-	their non-async counterparts.  The differences are: they do
-	not acquire the PM mutex, and they use a workqueue to do their
+	their non-async counterparts.  The big difference is that they
+	use a workqueue to do the resume or suspend part of their
 	jobs.  As a result they can be called in an atomic context,
 	such as an URB's completion handler, but when they return the
-	device will not generally not yet be in the desired state.
+	device will generally not yet be in the desired state.
 
 	usb_autopm_get_interface_no_resume() and
 	usb_autopm_put_interface_no_suspend() merely increment or
-	decrement the pm_usage_count value; they do not attempt to
-	carry out an autoresume or an autosuspend.  Hence they can be
-	called in an atomic context.
+	decrement the usage counter; they do not attempt to carry out
+	an autoresume or an autosuspend.  Hence they can be called in
+	an atomic context.
 
-The conventional usage pattern is that a driver calls
+The simplest usage pattern is that a driver calls
 usb_autopm_get_interface() in its open routine and
-usb_autopm_put_interface() in its close or release routine.  But
-other patterns are possible.
+usb_autopm_put_interface() in its close or release routine.  But other
+patterns are possible.
 
 The autosuspend attempts mentioned above will often fail for one
 reason or another.  For example, the power/level attribute might be
 set to "on", or another interface in the same device might not be
 idle.  This is perfectly normal.  If the reason for failure was that
-the device hasn't been idle for long enough, a delayed workqueue
-routine is automatically set up to carry out the operation when the
-autosuspend idle-delay has expired.
+the device hasn't been idle for long enough, a timer is scheduled to
+carry out the operation automatically when the autosuspend idle-delay
+has expired.
 
 Autoresume attempts also can fail, although failure would mean that
 the device is no longer present or operating properly.  Unlike
-autosuspend, there's no delay for an autoresume.
+autosuspend, there's no idle-delay for an autoresume.
 
 
 	Other parts of the driver interface
@@ -413,26 +412,27 @@ though, setting this flag won't cause the kernel to autoresume it.
 Normally a driver would set this flag in its probe method, at which
 time the device is guaranteed not to be autosuspended.)
 
-The synchronous usb_autopm_* routines have to run in a sleepable
-process context; they must not be called from an interrupt handler or
-while holding a spinlock.  In fact, the entire autosuspend mechanism
-is not well geared toward interrupt-driven operation.  However there
-is one thing a driver can do in an interrupt handler:
+If a driver does its I/O asynchronously in interrupt context, it
+should call usb_autopm_get_interface_async() before starting output and
+usb_autopm_put_interface_async() when the output queue drains.  When
+it receives an input event, it should call
 
 	usb_mark_last_busy(struct usb_device *udev);
 
-This sets udev->last_busy to the current time.  udev->last_busy is the
-field used for idle-delay calculations; updating it will cause any
-pending autosuspend to be moved back.  The usb_autopm_* routines will
-also set the last_busy field to the current time.
-
-Calling urb_mark_last_busy() from within an URB completion handler is
-subject to races: The kernel may have just finished deciding the
-device has been idle for long enough but not yet gotten around to
-calling the driver's suspend method.  The driver would have to be
-responsible for synchronizing its suspend method with its URB
-completion handler and causing the autosuspend to fail with -EBUSY if
-an URB had completed too recently.
+in the event handler.  This sets udev->last_busy to the current time.
+udev->last_busy is the field used for idle-delay calculations;
+updating it will cause any pending autosuspend to be moved back.  Most
+of the usb_autopm_* routines will also set the last_busy field to the
+current time.
+
+Asynchronous operation is always subject to races.  For example, a
+driver may call one of the usb_autopm_*_interface_async() routines at
+a time when the core has just finished deciding the device has been
+idle for long enough but not yet gotten around to calling the driver's
+suspend method.  The suspend method must be responsible for
+synchronizing with the output request routine and the URB completion
+handler; it should cause autosuspends to fail with -EBUSY if the
+driver needs to use the device.
 
 External suspend calls should never be allowed to fail in this way,
 only autosuspend calls.  The driver can tell them apart by checking
@@ -440,75 +440,23 @@ the PM_EVENT_AUTO bit in the message.event argument to the suspend
 method; this bit will be set for internal PM events (autosuspend) and
 clear for external PM events.
 
-Many of the ingredients in the autosuspend framework are oriented
-towards interfaces: The usb_interface structure contains the
-pm_usage_cnt field, and the usb_autopm_* routines take an interface
-pointer as their argument.  But somewhat confusingly, a few of the
-pieces (i.e., usb_mark_last_busy()) use the usb_device structure
-instead.  Drivers need to keep this straight; they can call
-interface_to_usbdev() to find the device structure for a given
-interface.
 
+	Mutual exclusion
+	----------------
 
-	Locking requirements
-	--------------------
-
-All three suspend/resume methods are always called while holding the
-usb_device's PM mutex.  For external events -- but not necessarily for
-autosuspend or autoresume -- the device semaphore (udev->dev.sem) will
-also be held.  This implies that external suspend/resume events are
-mutually exclusive with calls to probe, disconnect, pre_reset, and
-post_reset; the USB core guarantees that this is true of internal
-suspend/resume events as well.
+For external events -- but not necessarily for autosuspend or
+autoresume -- the device semaphore (udev->dev.sem) will be held when a
+suspend or resume method is called.  This implies that external
+suspend/resume events are mutually exclusive with calls to probe,
+disconnect, pre_reset, and post_reset; the USB core guarantees that
+this is true of autosuspend/autoresume events as well.
 
 If a driver wants to block all suspend/resume calls during some
-critical section, it can simply acquire udev->pm_mutex. Note that
-calls to resume may be triggered indirectly. Block IO due to memory
-allocations can make the vm subsystem resume a device. Thus while
-holding this lock you must not allocate memory with GFP_KERNEL or
-GFP_NOFS.
-
-Alternatively, if the critical section might call some of the
-usb_autopm_* routines, the driver can avoid deadlock by doing:
-
-	down(&udev->dev.sem);
-	rc = usb_autopm_get_interface(intf);
-
-and at the end of the critical section:
-
-	if (!rc)
-		usb_autopm_put_interface(intf);
-	up(&udev->dev.sem);
-
-Holding the device semaphore will block all external PM calls, and the
-usb_autopm_get_interface() will prevent any internal PM calls, even if
-it fails.  (Exercise: Why?)
-
-The rules for locking order are:
-
-	Never acquire any device semaphore while holding any PM mutex.
-
-	Never acquire udev->pm_mutex while holding the PM mutex for
-	a device that isn't a descendant of udev.
-
-In other words, PM mutexes should only be acquired going up the device
-tree, and they should be acquired only after locking all the device
-semaphores you need to hold.  These rules don't matter to drivers very
-much; they usually affect just the USB core.
-
-Still, drivers do need to be careful.  For example, many drivers use a
-private mutex to synchronize their normal I/O activities with their
-disconnect method.  Now if the driver supports autosuspend then it
-must call usb_autopm_put_interface() from somewhere -- maybe from its
-close method.  It should make the call while holding the private mutex,
-since a driver shouldn't call any of the usb_autopm_* functions for an
-interface from which it has been unbound.
-
-But the usb_autpm_* routines always acquire the device's PM mutex, and
-consequently the locking order has to be: private mutex first, PM
-mutex second.  Since the suspend method is always called with the PM
-mutex held, it mustn't try to acquire the private mutex.  It has to
-synchronize with the driver's I/O activities in some other way.
+critical section, the best way is to lock the device and call
+usb_autopm_get_interface() (and do the reverse at the end of the
+critical section).  Holding the device semaphore will block all
+external PM calls, and the usb_autopm_get_interface() will prevent any
+internal PM calls, even if it fails.  (Exercise: Why?)
 
 
 	Interaction between dynamic PM and system PM
@@ -517,22 +465,11 @@ synchronize with the driver's I/O activities in some other way.
 Dynamic power management and system power management can interact in
 a couple of ways.
 
-Firstly, a device may already be manually suspended or autosuspended
-when a system suspend occurs.  Since system suspends are supposed to
-be as transparent as possible, the device should remain suspended
-following the system resume.  The 2.6.23 kernel obeys this principle
-for manually suspended devices but not for autosuspended devices; they
-do get resumed when the system wakes up.  (Presumably they will be
-autosuspended again after their idle-delay time expires.)  In later
-kernels this behavior will be fixed.
-
-(There is an exception.  If a device would undergo a reset-resume
-instead of a normal resume, and the device is enabled for remote
-wakeup, then the reset-resume takes place even if the device was
-already suspended when the system suspend began.  The justification is
-that a reset-resume is a kind of remote-wakeup event.  Or to put it
-another way, a device which needs a reset won't be able to generate
-normal remote-wakeup signals, so it ought to be resumed immediately.)
+Firstly, a device may already be autosuspended when a system suspend
+occurs.  Since system suspends are supposed to be as transparent as
+possible, the device should remain suspended following the system
+resume.  But this theory may not work out well in practice; over time
+the kernel's behavior in this regard has changed.
 
 Secondly, a dynamic power-management event may occur as a system
 suspend is underway.  The window for this is short, since system
diff --git a/drivers/usb/core/Kconfig b/drivers/usb/core/Kconfig
index ad925946f86..97a819c23ef 100644
--- a/drivers/usb/core/Kconfig
+++ b/drivers/usb/core/Kconfig
@@ -91,8 +91,8 @@ config USB_DYNAMIC_MINORS
 	  If you are unsure about this, say N here.
 
 config USB_SUSPEND
-	bool "USB selective suspend/resume and wakeup"
-	depends on USB && PM
+	bool "USB runtime power management (suspend/resume and wakeup)"
+	depends on USB && PM_RUNTIME
 	help
 	  If you say Y here, you can use driver calls or the sysfs
 	  "power/level" file to suspend or resume individual USB
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 638d54693a1..6850ec6576f 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -25,7 +25,7 @@
 #include <linux/device.h>
 #include <linux/usb.h>
 #include <linux/usb/quirks.h>
-#include <linux/workqueue.h>
+#include <linux/pm_runtime.h>
 #include "hcd.h"
 #include "usb.h"
 
@@ -221,7 +221,7 @@ static int usb_probe_device(struct device *dev)
 {
 	struct usb_device_driver *udriver = to_usb_device_driver(dev->driver);
 	struct usb_device *udev = to_usb_device(dev);
-	int error = -ENODEV;
+	int error = 0;
 
 	dev_dbg(dev, "%s\n", __func__);
 
@@ -230,18 +230,23 @@ static int usb_probe_device(struct device *dev)
 	/* The device should always appear to be in use
 	 * unless the driver suports autosuspend.
 	 */
-	udev->pm_usage_cnt = !(udriver->supports_autosuspend);
+	if (!udriver->supports_autosuspend)
+		error = usb_autoresume_device(udev);
 
-	error = udriver->probe(udev);
+	if (!error)
+		error = udriver->probe(udev);
 	return error;
 }
 
 /* called from driver core with dev locked */
 static int usb_unbind_device(struct device *dev)
 {
+	struct usb_device *udev = to_usb_device(dev);
 	struct usb_device_driver *udriver = to_usb_device_driver(dev->driver);
 
-	udriver->disconnect(to_usb_device(dev));
+	udriver->disconnect(udev);
+	if (!udriver->supports_autosuspend)
+		usb_autosuspend_device(udev);
 	return 0;
 }
 
@@ -293,17 +298,16 @@ static int usb_probe_interface(struct device *dev)
 	if (error)
 		return error;
 
-	/* Interface "power state" doesn't correspond to any hardware
-	 * state whatsoever.  We use it to record when it's bound to
-	 * a driver that may start I/0:  it's not frozen/quiesced.
-	 */
-	mark_active(intf);
 	intf->condition = USB_INTERFACE_BINDING;
 
-	/* The interface should always appear to be in use
-	 * unless the driver suports autosuspend.
+	/* Bound interfaces are initially active.  They are
+	 * runtime-PM-enabled only if the driver has autosuspend support.
+	 * They are sensitive to their children's power states.
 	 */
-	atomic_set(&intf->pm_usage_cnt, !driver->supports_autosuspend);
+	pm_runtime_set_active(dev);
+	pm_suspend_ignore_children(dev, false);
+	if (driver->supports_autosuspend)
+		pm_runtime_enable(dev);
 
 	/* Carry out a deferred switch to altsetting 0 */
 	if (intf->needs_altsetting0) {
@@ -323,10 +327,14 @@ static int usb_probe_interface(struct device *dev)
 	return error;
 
  err:
-	mark_quiesced(intf);
 	intf->needs_remote_wakeup = 0;
 	intf->condition = USB_INTERFACE_UNBOUND;
 	usb_cancel_queued_reset(intf);
+
+	/* Unbound interfaces are always runtime-PM-disabled and -suspended */
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+
 	usb_autosuspend_device(udev);
 	return error;
 }
@@ -376,9 +384,17 @@ static int usb_unbind_interface(struct device *dev)
 	usb_set_intfdata(intf, NULL);
 
 	intf->condition = USB_INTERFACE_UNBOUND;
-	mark_quiesced(intf);
 	intf->needs_remote_wakeup = 0;
 
+	/* Unbound interfaces are always runtime-PM-disabled and -suspended */
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+
+	/* Undo any residual pm_autopm_get_interface_* calls */
+	for (r = atomic_read(&intf->pm_usage_cnt); r > 0; --r)
+		usb_autopm_put_interface_no_suspend(intf);
+	atomic_set(&intf->pm_usage_cnt, 0);
+
 	if (!error)
 		usb_autosuspend_device(udev);
 
@@ -409,7 +425,6 @@ int usb_driver_claim_interface(struct usb_driver *driver,
 				struct usb_interface *iface, void *priv)
 {
 	struct device *dev = &iface->dev;
-	struct usb_device *udev = interface_to_usbdev(iface);
 	int retval = 0;
 
 	if (dev->driver)
@@ -419,11 +434,16 @@ int usb_driver_claim_interface(struct usb_driver *driver,
 	usb_set_intfdata(iface, priv);
 	iface->needs_binding = 0;
 
-	usb_pm_lock(udev);
 	iface->condition = USB_INTERFACE_BOUND;
-	mark_active(iface);
-	atomic_set(&iface->pm_usage_cnt, !driver->supports_autosuspend);
-	usb_pm_unlock(udev);
+
+	/* Bound interfaces are initially active.  They are
+	 * runtime-PM-enabled only if the driver has autosuspend support.
+	 * They are sensitive to their children's power states.
+	 */
+	pm_runtime_set_active(dev);
+	pm_suspend_ignore_children(dev, false);
+	if (driver->supports_autosuspend)
+		pm_runtime_enable(dev);
 
 	/* if interface was already added, bind now; else let
 	 * the future device_add() bind it, bypassing probe()
@@ -982,7 +1002,6 @@ static void do_unbind_rebind(struct usb_device *udev, int action)
 	}
 }
 
-/* Caller has locked udev's pm_mutex */
 static int usb_suspend_device(struct usb_device *udev, pm_message_t msg)
 {
 	struct usb_device_driver	*udriver;
@@ -1006,7 +1025,6 @@ static int usb_suspend_device(struct usb_device *udev, pm_message_t msg)
 	return status;
 }
 
-/* Caller has locked udev's pm_mutex */
 static int usb_resume_device(struct usb_device *udev, pm_message_t msg)
 {
 	struct usb_device_driver	*udriver;
@@ -1040,27 +1058,20 @@ static int usb_resume_device(struct usb_device *udev, pm_message_t msg)
 	return status;
 }
 
-/* Caller has locked intf's usb_device's pm mutex */
 static int usb_suspend_interface(struct usb_device *udev,
 		struct usb_interface *intf, pm_message_t msg)
 {
 	struct usb_driver	*driver;
 	int			status = 0;
 
-	/* with no hardware, USB interfaces only use FREEZE and ON states */
-	if (udev->state == USB_STATE_NOTATTACHED || !is_active(intf))
-		goto done;
-
-	/* This can happen; see usb_driver_release_interface() */
-	if (intf->condition == USB_INTERFACE_UNBOUND)
+	if (udev->state == USB_STATE_NOTATTACHED ||
+			intf->condition == USB_INTERFACE_UNBOUND)
 		goto done;
 	driver = to_usb_driver(intf->dev.driver);
 
 	if (driver->suspend) {
 		status = driver->suspend(intf, msg);
-		if (status == 0)
-			mark_quiesced(intf);
-		else if (!(msg.event & PM_EVENT_AUTO))
+		if (status && !(msg.event & PM_EVENT_AUTO))
 			dev_err(&intf->dev, "%s error %d\n",
 					"suspend", status);
 	} else {
@@ -1068,7 +1079,6 @@ static int usb_suspend_interface(struct usb_device *udev,
 		intf->needs_binding = 1;
 		dev_warn(&intf->dev, "no %s for driver %s?\n",
 				"suspend", driver->name);
-		mark_quiesced(intf);
 	}
 
  done:
@@ -1076,14 +1086,13 @@ static int usb_suspend_interface(struct usb_device *udev,
 	return status;
 }
 
-/* Caller has locked intf's usb_device's pm_mutex */
 static int usb_resume_interface(struct usb_device *udev,
 		struct usb_interface *intf, pm_message_t msg, int reset_resume)
 {
 	struct usb_driver	*driver;
 	int			status = 0;
 
-	if (udev->state == USB_STATE_NOTATTACHED || is_active(intf))
+	if (udev->state == USB_STATE_NOTATTACHED)
 		goto done;
 
 	/* Don't let autoresume interfere with unbinding */
@@ -1134,90 +1143,11 @@ static int usb_resume_interface(struct usb_device *udev,
 
 done:
 	dev_vdbg(&intf->dev, "%s: status %d\n", __func__, status);
-	if (status == 0 && intf->condition == USB_INTERFACE_BOUND)
-		mark_active(intf);
 
 	/* Later we will unbind the driver and/or reprobe, if necessary */
 	return status;
 }
 
-#ifdef	CONFIG_USB_SUSPEND
-
-/* Internal routine to check whether we may autosuspend a device. */
-static int autosuspend_check(struct usb_device *udev, int reschedule)
-{
-	int			i;
-	struct usb_interface	*intf;
-	unsigned long		suspend_time, j;
-
-	/* For autosuspend, fail fast if anything is in use or autosuspend
-	 * is disabled.  Also fail if any interfaces require remote wakeup
-	 * but it isn't available.
-	 */
-	if (udev->pm_usage_cnt > 0)
-		return -EBUSY;
-	if (udev->autosuspend_delay < 0 || udev->autosuspend_disabled)
-		return -EPERM;
-
-	suspend_time = udev->last_busy + udev->autosuspend_delay;
-	if (udev->actconfig) {
-		for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
-			intf = udev->actconfig->interface[i];
-			if (!is_active(intf))
-				continue;
-			if (atomic_read(&intf->pm_usage_cnt) > 0)
-				return -EBUSY;
-			if (intf->needs_remote_wakeup &&
-					!udev->do_remote_wakeup) {
-				dev_dbg(&udev->dev, "remote wakeup needed "
-						"for autosuspend\n");
-				return -EOPNOTSUPP;
-			}
-
-			/* Don't allow autosuspend if the device will need
-			 * a reset-resume and any of its interface drivers
-			 * doesn't include support.
-			 */
-			if (udev->quirks & USB_QUIRK_RESET_RESUME) {
-				struct usb_driver *driver;
-
-				driver = to_usb_driver(intf->dev.driver);
-				if (!driver->reset_resume ||
-				    intf->needs_remote_wakeup)
-					return -EOPNOTSUPP;
-			}
-		}
-	}
-
-	/* If everything is okay but the device hasn't been idle for long
-	 * enough, queue a delayed autosuspend request.  If the device
-	 * _has_ been idle for long enough and the reschedule flag is set,
-	 * likewise queue a delayed (1 second) autosuspend request.
-	 */
-	j = jiffies;
-	if (time_before(j, suspend_time))
-		reschedule = 1;
-	else
-		suspend_time = j + HZ;
-	if (reschedule) {
-		if (!timer_pending(&udev->autosuspend.timer)) {
-			queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
-				round_jiffies_up_relative(suspend_time - j));
-		}
-		return -EAGAIN;
-	}
-	return 0;
-}
-
-#else
-
-static inline int autosuspend_check(struct usb_device *udev, int reschedule)
-{
-	return 0;
-}
-
-#endif	/* CONFIG_USB_SUSPEND */
-
 /**
  * usb_suspend_both - suspend a USB device and its interfaces
  * @udev: the usb_device to suspend
@@ -1229,27 +1159,12 @@ static inline int autosuspend_check(struct usb_device *udev, int reschedule)
  * all the interfaces which were suspended are resumed so that they remain
  * in the same state as the device.
  *
- * If an autosuspend is in progress the routine checks first to make sure
- * that neither the device itself or any of its active interfaces is in use
- * (pm_usage_cnt is greater than 0).  If they are, the autosuspend fails.
- *
- * If the suspend succeeds, the routine recursively queues an autosuspend
- * request for @udev's parent device, thereby propagating the change up
- * the device tree.  If all of the parent's children are now suspended,
- * the parent will autosuspend in turn.
- *
- * The suspend method calls are subject to mutual exclusion under control
- * of @udev's pm_mutex.  Many of these calls are also under the protection
- * of @udev's device lock (including all requests originating outside the
- * USB subsystem), but autosuspend requests generated by a child device or
- * interface driver may not be.  Usbcore will insure that the method calls
- * do not arrive during bind, unbind, or reset operations.  However, drivers
- * must be prepared to handle suspend calls arriving at unpredictable times.
- * The only way to block such calls is to do an autoresume (preventing
- * autosuspends) while holding @udev's device lock (preventing outside
- * suspends).
- *
- * The caller must hold @udev->pm_mutex.
+ * Autosuspend requests originating from a child device or an interface
+ * driver may be made without the protection of @udev's device lock, but
+ * all other suspend calls will hold the lock.  Usbcore will insure that
+ * method calls do not arrive during bind, unbind, or reset operations.
+ * However drivers must be prepared to handle suspend calls arriving at
+ * unpredictable times.
  *
  * This routine can run only in process context.
  */
@@ -1258,20 +1173,11 @@ static int usb_suspend_both(struct usb_device *udev, pm_message_t msg)
 	int			status = 0;
 	int			i = 0;
 	struct usb_interface	*intf;
-	struct usb_device	*parent = udev->parent;
 
 	if (udev->state == USB_STATE_NOTATTACHED ||
 			udev->state == USB_STATE_SUSPENDED)
 		goto done;
 
-	udev->do_remote_wakeup = device_may_wakeup(&udev->dev);
-
-	if (msg.event & PM_EVENT_AUTO) {
-		status = autosuspend_check(udev, 0);
-		if (status < 0)
-			goto done;
-	}
-
 	/* Suspend all the interfaces and then udev itself */
 	if (udev->actconfig) {
 		for (; i < udev->actconfig->desc.bNumInterfaces; i++) {
@@ -1286,35 +1192,21 @@ static int usb_suspend_both(struct usb_device *udev, pm_message_t msg)
 
 	/* If the suspend failed, resume interfaces that did get suspended */
 	if (status != 0) {
-		pm_message_t msg2;
-
-		msg2.event = msg.event ^ (PM_EVENT_SUSPEND | PM_EVENT_RESUME);
+		msg.event ^= (PM_EVENT_SUSPEND | PM_EVENT_RESUME);
 		while (--i >= 0) {
 			intf = udev->actconfig->interface[i];
-			usb_resume_interface(udev, intf, msg2, 0);
+			usb_resume_interface(udev, intf, msg, 0);
 		}
 
-		/* Try another autosuspend when the interfaces aren't busy */
-		if (msg.event & PM_EVENT_AUTO)
-			autosuspend_check(udev, status == -EBUSY);
-
-	/* If the suspend succeeded then prevent any more URB submissions,
-	 * flush any outstanding URBs, and propagate the suspend up the tree.
+	/* If the suspend succeeded then prevent any more URB submissions
+	 * and flush any outstanding URBs.
 	 */
 	} else {
-		cancel_delayed_work(&udev->autosuspend);
 		udev->can_submit = 0;
 		for (i = 0; i < 16; ++i) {
 			usb_hcd_flush_endpoint(udev, udev->ep_out[i]);
 			usb_hcd_flush_endpoint(udev, udev->ep_in[i]);
 		}
-
-		/* If this is just a FREEZE or a PRETHAW, udev might
-		 * not really be suspended.  Only true suspends get
-		 * propagated up the device tree.
-		 */
-		if (parent && udev->state == USB_STATE_SUSPENDED)
-			usb_autosuspend_device(parent);
 	}
 
  done:
@@ -1331,23 +1223,12 @@ static int usb_suspend_both(struct usb_device *udev, pm_message_t msg)
  * the resume method for @udev and then calls the resume methods for all
  * the interface drivers in @udev.
  *
- * Before starting the resume, the routine calls itself recursively for
- * the parent device of @udev, thereby propagating the change up the device
- * tree and assuring that @udev will be able to resume.  If the parent is
- * unable to resume successfully, the routine fails.
- *
- * The resume method calls are subject to mutual exclusion under control
- * of @udev's pm_mutex.  Many of these calls are also under the protection
- * of @udev's device lock (including all requests originating outside the
- * USB subsystem), but autoresume requests generated by a child device or
- * interface driver may not be.  Usbcore will insure that the method calls
- * do not arrive during bind, unbind, or reset operations.  However, drivers
- * must be prepared to handle resume calls arriving at unpredictable times.
- * The only way to block such calls is to do an autoresume (preventing
- * other autoresumes) while holding @udev's device lock (preventing outside
- * resumes).
- *
- * The caller must hold @udev->pm_mutex.
+ * Autoresume requests originating from a child device or an interface
+ * driver may be made without the protection of @udev's device lock, but
+ * all other resume calls will hold the lock.  Usbcore will insure that
+ * method calls do not arrive during bind, unbind, or reset operations.
+ * However drivers must be prepared to handle resume calls arriving at
+ * unpredictable times.
  *
  * This routine can run only in process context.
  */
@@ -1356,48 +1237,18 @@ static int usb_resume_both(struct usb_device *udev, pm_message_t msg)
 	int			status = 0;
 	int			i;
 	struct usb_interface	*intf;
-	struct usb_device	*parent = udev->parent;
 
-	cancel_delayed_work(&udev->autosuspend);
 	if (udev->state == USB_STATE_NOTATTACHED) {
 		status = -ENODEV;
 		goto done;
 	}
 	udev->can_submit = 1;
 
-	/* Propagate the resume up the tree, if necessary */
-	if (udev->state == USB_STATE_SUSPENDED) {
-		if (parent) {
-			status = usb_autoresume_device(parent);
-			if (status == 0) {
-				status = usb_resume_device(udev, msg);
-				if (status || udev->state ==
-						USB_STATE_NOTATTACHED) {
-					usb_autosuspend_device(parent);
-
-					/* It's possible usb_resume_device()
-					 * failed after the port was
-					 * unsuspended, causing udev to be
-					 * logically disconnected.  We don't
-					 * want usb_disconnect() to autosuspend
-					 * the parent again, so tell it that
-					 * udev disconnected while still
-					 * suspended. */
-					if (udev->state ==
-							USB_STATE_NOTATTACHED)
-						udev->discon_suspended = 1;
-				}
-			}
-		} else {
-
-			/* We can't progagate beyond the USB subsystem,
-			 * so if a root hub's controller is suspended
-			 * then we're stuck. */
-			status = usb_resume_device(udev, msg);
-		}
-	} else if (udev->reset_resume)
+	/* Resume the device */
+	if (udev->state == USB_STATE_SUSPENDED || udev->reset_resume)
 		status = usb_resume_device(udev, msg);
 
+	/* Resume the interfaces */
 	if (status == 0 && udev->actconfig) {
 		for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
 			intf = udev->actconfig->interface[i];
@@ -1413,104 +1264,46 @@ static int usb_resume_both(struct usb_device *udev, pm_message_t msg)
 	return status;
 }
 
-/**
- * usb_external_suspend_device - external suspend of a USB device and its interfaces
- * @udev: the usb_device to suspend
- * @msg: Power Management message describing this state transition
- *
- * This routine handles external suspend requests: ones not generated
- * internally by a USB driver (autosuspend) but rather coming from the user
- * (via sysfs) or the PM core (system sleep).  The suspend will be carried
- * out regardless of @udev's usage counter or those of its interfaces,
- * and regardless of whether or not remote wakeup is enabled.  Of course,
- * interface drivers still have the option of failing the suspend (if
- * there are unsuspended children, for example).
- *
- * The caller must hold @udev's device lock.
- */
-int usb_external_suspend_device(struct usb_device *udev, pm_message_t msg)
-{
-	int	status;
-
-	do_unbind_rebind(udev, DO_UNBIND);
-	usb_pm_lock(udev);
-	status = usb_suspend_both(udev, msg);
-	usb_pm_unlock(udev);
-	return status;
-}
-
-/**
- * usb_external_resume_device - external resume of a USB device and its interfaces
- * @udev: the usb_device to resume
- * @msg: Power Management message describing this state transition
- *
- * This routine handles external resume requests: ones not generated
- * internally by a USB driver (autoresume) but rather coming from the user
- * (via sysfs), the PM core (system resume), or the device itself (remote
- * wakeup).  @udev's usage counter is unaffected.
- *
- * The caller must hold @udev's device lock.
- */
-int usb_external_resume_device(struct usb_device *udev, pm_message_t msg)
-{
-	int	status;
-
-	usb_pm_lock(udev);
-	status = usb_resume_both(udev, msg);
-	udev->last_busy = jiffies;
-	usb_pm_unlock(udev);
-	if (status == 0)
-		do_unbind_rebind(udev, DO_REBIND);
-
-	/* Now that the device is awake, we can start trying to autosuspend
-	 * it again. */
-	if (status == 0)
-		usb_try_autosuspend_device(udev);
-	return status;
-}
-
+/* The device lock is held by the PM core */
 int usb_suspend(struct device *dev, pm_message_t msg)
 {
-	struct usb_device	*udev;
-
-	udev = to_usb_device(dev);
+	struct usb_device	*udev = to_usb_device(dev);
 
-	/* If udev is already suspended, we can skip this suspend and
-	 * we should also skip the upcoming system resume.  High-speed
-	 * root hubs are an exception; they need to resume whenever the
-	 * system wakes up in order for USB-PERSIST port handover to work
-	 * properly.
-	 */
-	if (udev->state == USB_STATE_SUSPENDED) {
-		if (udev->parent || udev->speed != USB_SPEED_HIGH)
-			udev->skip_sys_resume = 1;
-		return 0;
-	}
-
-	udev->skip_sys_resume = 0;
-	return usb_external_suspend_device(udev, msg);
+	do_unbind_rebind(udev, DO_UNBIND);
+	udev->do_remote_wakeup = device_may_wakeup(&udev->dev);
+	return usb_suspend_both(udev, msg);
 }
 
+/* The device lock is held by the PM core */
 int usb_resume(struct device *dev, pm_message_t msg)
 {
-	struct usb_device	*udev;
+	struct usb_device	*udev = to_usb_device(dev);
 	in