Commit 9bbdf1e0 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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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: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 0c590e23
......@@ -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
......
......@@ -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
......
This diff is collapsed.
......@@ -39,6 +39,7 @@
#include <linux/platform_device.h>
#include <linux/workqueue.h>
#include <linux/mutex.h>
#include <linux/pm_runtime.h>
#include <linux/usb.h>
......@@ -1858,6 +1859,10 @@ int hcd_bus_resume(struct usb_device *rhdev, pm_message_t msg)
return status;
}
#endif /* CONFIG_PM */
#ifdef CONFIG_USB_SUSPEND
/* Workqueue routine for root-hub remote wakeup */
static void hcd_resume_work(struct work_struct *work)
{
......@@ -1884,12 +1889,12 @@ void usb_hcd_resume_root_hub (struct usb_hcd *hcd)
spin_lock_irqsave (&hcd_root_hub_lock, flags);
if (hcd->rh_registered)
queue_work(ksuspend_usb_wq, &hcd->wakeup_work);
queue_work(pm_wq, &hcd->wakeup_work);
spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
}
EXPORT_SYMBOL_GPL(usb_hcd_resume_root_hub);
#endif
#endif /* CONFIG_USB_SUSPEND */
/*-------------------------------------------------------------------------*/
......@@ -2034,7 +2039,7 @@ struct usb_hcd *usb_create_hcd (const struct hc_driver *driver,
init_timer(&hcd->rh_timer);
hcd->rh_timer.function = rh_timer_func;
hcd->rh_timer.data = (unsigned long) hcd;
#ifdef CONFIG_PM
#ifdef CONFIG_USB_SUSPEND
INIT_WORK(&hcd->wakeup_work, hcd_resume_work);
#endif
mutex_init(&hcd->bandwidth_mutex);
......@@ -2234,7 +2239,7 @@ void usb_remove_hcd(struct usb_hcd *hcd)
hcd->rh_registered = 0;
spin_unlock_irq (&hcd_root_hub_lock);
#ifdef CONFIG_PM
#ifdef CONFIG_USB_SUSPEND
cancel_work_sync(&hcd->wakeup_work);
#endif
......
......@@ -80,7 +80,7 @@ struct usb_hcd {
struct timer_list rh_timer; /* drives root-hub polling */
struct urb *status_urb; /* the current status urb */
#ifdef CONFIG_PM
#ifdef CONFIG_USB_SUSPEND
struct work_struct wakeup_work; /* for remote wakeup */
#endif
......@@ -464,16 +464,20 @@ extern int usb_find_interface_driver(struct usb_device *dev,
#define usb_endpoint_out(ep_dir) (!((ep_dir) & USB_DIR_IN))
#ifdef CONFIG_PM
extern void usb_hcd_resume_root_hub(struct usb_hcd *hcd);
extern void usb_root_hub_lost_power(struct usb_device *rhdev);
extern int hcd_bus_suspend(struct usb_device *rhdev, pm_message_t msg);
extern int hcd_bus_resume(struct usb_device *rhdev, pm_message_t msg);
#endif /* CONFIG_PM */
#ifdef CONFIG_USB_SUSPEND
extern void usb_hcd_resume_root_hub(struct usb_hcd *hcd);
#else
static inline void usb_hcd_resume_root_hub(struct usb_hcd *hcd)
{
return;
}
#endif /* CONFIG_PM */
#endif /* CONFIG_USB_SUSPEND */
/*
* USB device fs stuff
......
......@@ -22,6 +22,7 @@
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/freezer.h>
#include <linux/pm_runtime.h>
#include <asm/uaccess.h>
#include <asm/byteorder.h>
......@@ -71,7 +72,6 @@ struct usb_hub {
unsigned mA_per_port; /* current for each child */
unsigned init_done:1;
unsigned limited_power:1;
unsigned quiescing:1;
unsigned disconnected:1;
......@@ -820,7 +820,6 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
}
init3:
hub->quiescing = 0;
hub->init_done = 1;
status = usb_submit_urb(hub->urb, GFP_NOIO);
if (status < 0)
......@@ -861,11 +860,6 @@ static void hub_quiesce(struct usb_hub *hub, enum hub_quiescing_type type)
int i;
cancel_delayed_work_sync(&hub->init_work);
if (!hub->init_done) {
hub->init_done = 1;
usb_autopm_put_interface_no_suspend(
to_usb_interface(hub->intfdev));
}
/* khubd and related activity won't re-trigger */
hub->quiescing = 1;
......@@ -1405,10 +1399,8 @@ static void recursively_mark_NOTATTACHED(struct usb_device *udev)
if (udev->children[i])
recursively_mark_NOTATTACHED(udev->children[i]);
}
if (udev->state == USB_STATE_SUSPENDED) {
udev->discon_suspended = 1;
if (udev->state == USB_STATE_SUSPENDED)
udev->active_duration -= jiffies;
}
udev->state = USB_STATE_NOTATTACHED;
}
......@@ -1532,31 +1524,6 @@ static void update_address(struct usb_device *udev, int devnum)
udev->devnum = devnum;
}
#ifdef CONFIG_USB_SUSPEND
static void usb_stop_pm(struct usb_device *udev)
{
/* Synchronize with the ksuspend thread to prevent any more
* autosuspend requests from being submitted, and decrement
* the parent's count of unsuspended children.
*/
usb_pm_lock(udev);
if (udev->parent && !udev->discon_suspended)
usb_autosuspend_device(udev->parent);
usb_pm_unlock(udev);
/* Stop any autosuspend or autoresume requests already submitted */
cancel_delayed_work_sync(&udev->autosuspend);
cancel_work_sync(&udev->autoresume);
}
#else
static inline void usb_stop_pm(struct usb_device *udev)
{ }
#endif
/**
* usb_disconnect - disconnect a device (usbcore-internal)
* @pdev: pointer to device being disconnected
......@@ -1625,8 +1592,6 @@ void usb_disconnect(struct usb_device **pdev)
*pdev = NULL;
spin_unlock_irq(&device_state_lock);
usb_stop_pm(udev);
put_device(&udev->dev);
}
......@@ -1803,9 +1768,6 @@ int usb_new_device(struct usb_device *udev)
int err;
if (udev->parent) {
/* Increment the parent's count of unsuspended children */
usb_autoresume_device(udev->parent);
/* Initialize non-root-hub device wakeup to disabled;
* device (un)configuration controls wakeup capable
* sysfs power/wakeup controls wakeup enabled/disabled
......@@ -1814,6 +1776,10 @@ int usb_new_device(struct usb_device *udev)
device_set_wakeup_enable(&udev->dev, 1);
}
/* Tell the runtime-PM framework the device is active */
pm_runtime_set_active(&udev->dev);
pm_runtime_enable(&udev->dev);
usb_detect_quirks(udev);
err = usb_enumerate_device(udev); /* Read descriptors */
if (err < 0)
......@@ -1844,7 +1810,8 @@ int usb_new_device(struct usb_device *udev)
fail:
usb_set_device_state(udev, USB_STATE_NOTATTACHED);
usb_stop_pm(udev);
pm_runtime_disable(&udev->dev);
pm_runtime_set_suspended(&udev->dev);
return err;
}
......@@ -2408,8 +2375,11 @@ int usb_remote_wakeup(struct usb_device *udev)
if (udev->state == USB_STATE_SUSPENDED) {
dev_dbg(&udev->dev, "usb %sresume\n", "wakeup-");
usb_mark_last_busy(udev);
status = usb_external_resume_device(udev, PMSG_REMOTE_RESUME);
status = usb_autoresume_device(udev);
if (status == 0) {
/* Let the drivers do their thing, then... */
usb_autosuspend_device(udev);
}
}
return status;
}
......@@ -2446,11 +2416,6 @@ int usb_port_resume(struct usb_device *udev, pm_message_t msg)
return status;
}
int usb_remote_wakeup(struct usb_device *udev)
{
return 0;
}
#endif
static int hub_suspend(struct usb_interface *intf, pm_message_t msg)
......@@ -3268,7 +3233,7 @@ static void hub_events(void)
* disconnected while waiting for the lock to succeed. */
usb_lock_device(hdev);
if (unlikely(hub->disconnected))
goto loop2;
goto loop_disconnected;
/* If the hub has died, clean up after it */
if (hdev->state == USB_STATE_NOTATTACHED) {
......@@ -3428,7 +3393,7 @@ static void hub_events(void)
* kick_khubd() and allow autosuspend.
*/
usb_autopm_put_interface(intf);
loop2:
loop_disconnected:
usb_unlock_device(hdev);
kref_put(&hub->kref, hub_release);
......
......@@ -1843,7 +1843,6 @@ free_interfaces:
intf->dev.dma_mask = dev->dev.dma_mask;
INIT_WORK(&intf->reset_ws, __usb_queue_reset_device);
device_initialize(&intf->dev);
mark_quiesced(intf);
dev_set_name(&intf->dev, "%d-%s:%d.%d",
dev->bus->busnum, dev->devpath,
configuration, alt->desc.bInterfaceNumber);
......
......@@ -49,9 +49,6 @@ const char *usbcore_name = "usbcore";
static int nousb; /* Disable USB when built into kernel image */
/* Workqueue for autosuspend and for remote wakeup of root hubs */
struct workqueue_struct *ksuspend_usb_wq;
#ifdef CONFIG_USB_SUSPEND
static int usb_autosuspend_delay = 2; /* Default delay value,
* in seconds */
......@@ -264,23 +261,6 @@ static int usb_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
#ifdef CONFIG_PM
static int ksuspend_usb_init(void)
{
/* This workqueue is supposed to be both freezable and
* singlethreaded. Its job doesn't justify running on more
* than one CPU.
*/
ksuspend_usb_wq = create_freezeable_workqueue("ksuspend_usbd");
if (!ksuspend_usb_wq)
return -ENOMEM;
return 0;
}
static void ksuspend_usb_cleanup(void)
{
destroy_workqueue(ksuspend_usb_wq);
}
/* USB device Power-Management thunks.
* There's no need to distinguish here between quiescing a USB device
* and powering it down; the generic_suspend() routine takes care of
......@@ -296,7 +276,7 @@ static int usb_dev_prepare(struct device *dev)
static void usb_dev_complete(struct device *dev)
{
/* Currently used only for rebinding interfaces */
usb_resume(dev, PMSG_RESUME); /* Message event is meaningless */
usb_resume(dev, PMSG_ON); /* FIXME: change to PMSG_COMPLETE */
}
static int usb_dev_suspend(struct device *dev)
......@@ -342,9 +322,7 @@ static const struct dev_pm_ops usb_device_pm_ops = {
#else
#define ksuspend_usb_init() 0
#define ksuspend_usb_cleanup() do {} while (0)
#define usb_device_pm_ops (*(struct dev_pm_ops *)0)
#define usb_device_pm_ops (*(struct dev_pm_ops *) NULL)
#endif /* CONFIG_PM */
......@@ -472,9 +450,6 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent,
INIT_LIST_HEAD(&dev->filelist);
#ifdef CONFIG_PM
mutex_init(&dev->pm_mutex);
INIT_DELAYED_WORK(&dev->autosuspend, usb_autosuspend_work);
INIT_WORK(&dev->autoresume, usb_autoresume_work);
dev->autosuspend_delay = usb_autosuspend_delay * HZ;
dev->connect_time = jiffies;
dev->active_duration = -jiffies;
......@@ -1117,9 +1092,6 @@ static int __init usb_init(void)
if (retval)
goto out;
retval = ksuspend_usb_init();
if (retval)
goto out;
retval = bus_register(&usb_bus_type);
if (retval)
goto bus_register_failed;
......@@ -1159,7 +1131,7 @@ major_init_failed:
bus_notifier_failed:
bus_unregister(&usb_bus_type);
bus_register_failed:
ksuspend_usb_cleanup();
usb_debugfs_cleanup();
out:
return retval;
}
......@@ -1181,7 +1153,6 @@ static void __exit usb_exit(void)
usb_hub_cleanup();
bus_unregister_notifier(&usb_bus_type, &usb_bus_nb);
bus_unregister(&usb_bus_type);
ksuspend_usb_cleanup();
usb_debugfs_cleanup();
}
......
......@@ -55,25 +55,8 @@ extern void usb_major_cleanup(void);
extern int usb_suspend(struct device *dev, pm_message_t msg);
extern int usb_resume(struct device *dev, pm_message_t msg);