Alan Stern <stern@rowland.harvard.edu>
- November 10, 2009
+ December 11, 2009
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?
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
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
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
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
#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"
{
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__);
/* 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;
}
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) {
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;
}
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);
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)
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()
}
}
-/* 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;
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;
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 {
intf->needs_binding = 1;
dev_warn(&intf->dev, "no %s for driver %s?\n",
"suspend", driver->name);
- mark_quiesced(intf);
}
done:
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 */
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
* 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.
*/
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++) {
/* 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:
* 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.
*/
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];
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);
int status;
- udev = to_usb_device(dev);
+ /* For PM complete calls, all we do is rebind interfaces */
+ if (msg.event == PM_EVENT_ON) {
+ if (udev->state != USB_STATE_NOTATTACHED)
+ do_unbind_rebind(udev, DO_REBIND);
+ status = 0;
- /* If udev->skip_sys_resume is set then udev was already suspended
- * when the system sleep started, so we don't want to resume it
- * during this system wakeup.
+ /* For all other calls, take the device back to full power and
+ * tell the PM core in case it was autosuspended previously.
*/
- if (udev->skip_sys_resume)
- return 0;
- status = usb_external_resume_device(udev, msg);
+ } else {
+ status = usb_resume_both(udev, msg);
+ if (status == 0) {
+ pm_runtime_disable(dev);
+ pm_runtime_set_active(dev);
+ pm_runtime_enable(dev);
+ udev->last_busy = jiffies;
+ }
+ }
/* Avoid PM error messages for devices disconnected while suspended
* as we'll display regular disconnect messages just a bit later.
*/
if (status == -ENODEV)
- return 0;
+ status = 0;
return status;
}
}
EXPORT_SYMBOL_GPL(usb_disable_autosuspend);
-/* Internal routine to adjust a device's usage counter and change
- * its autosuspend state.
- */
-static int usb_autopm_do_device(struct usb_device *udev, int inc_usage_cnt)
-{
- int status = 0;
-
- usb_pm_lock(udev);
- udev->pm_usage_cnt += inc_usage_cnt;
- WARN_ON(udev->pm_usage_cnt < 0);
- if (inc_usage_cnt)
- udev->last_busy = jiffies;
- if (inc_usage_cnt >= 0 && udev->pm_usage_cnt > 0) {
- if (udev->state == USB_STATE_SUSPENDED)
- status = usb_resume_both(udev, PMSG_AUTO_RESUME);
- if (status != 0)
- udev->pm_usage_cnt -= inc_usage_cnt;
- else if (inc_usage_cnt)
- udev->last_busy = jiffies;
- } else if (inc_usage_cnt <= 0 && udev->pm_usage_cnt <= 0) {
- status = usb_suspend_both(udev, PMSG_AUTO_SUSPEND);
- }
- usb_pm_unlock(udev);
- return status;
-}
-
-/* usb_autosuspend_work - callback routine to autosuspend a USB device */
-void usb_autosuspend_work(struct work_struct *work)
-{
- struct usb_device *udev =
- container_of(work, struct usb_device, autosuspend.work);
-
- usb_autopm_do_device(udev, 0);
-}
-
-/* usb_autoresume_work - callback routine to autoresume a USB device */
-void usb_autoresume_work(struct work_struct *work)
-{
- struct usb_device *udev =
- container_of(work, struct usb_device, autoresume);
-
- /* Wake it up, let the drivers do their thing, and then put it
- * back to sleep.
- */
- if (usb_autopm_do_device(udev, 1) == 0)
- usb_autopm_do_device(udev, -1);
-}
-
/**
* usb_autosuspend_device - delayed autosuspend of a USB device and its interfaces
* @udev: the usb_device to autosuspend
* @udev and wants to allow it to autosuspend. Examples would be when
* @udev's device file in usbfs is closed or after a configuration change.
*
- * @udev's usage counter is decremented. If it or any of the usage counters
- * for an active interface is greater than 0, no autosuspend request will be
- * queued. (If an interface driver does not support autosuspend then its
- * usage counter is permanently positive.) Furthermore, if an interface
- * driver requires remote-wakeup capability during autosuspend but remote
- * wakeup is disabled, the autosuspend will fail.
+ * @udev's usage counter is decremented; if it drops to 0 and all the
+ * interfaces are inactive then a delayed autosuspend will be attempted.
+ * The attempt may fail (see autosuspend_check()).
*
* The caller must hold @udev's device lock.
*
{
int status;
- status = usb_autopm_do_device(udev, -1);
- dev_vdbg(&udev->dev, "%s: cnt %d\n",
- __func__, udev->pm_usage_cnt);
+ udev->last_busy = jiffies;
+ status = pm_runtime_put_sync(&udev->dev);
+ dev_vdbg(&udev->dev, "%s: cnt %d -> %d\n",
+ __func__, atomic_read(&udev->dev.power.usage_count),
+ status);
}
/**
* This routine should be called when a core subsystem thinks @udev may
* be ready to autosuspend.
*
- * @udev's usage counter left unchanged. If it or any of the usage counters
- * for an active interface is greater than 0, or autosuspend is not allowed
- * for any other reason, no autosuspend request will be queued.
+ * @udev's usage counter left unchanged. If it is 0 and all the interfaces
+ * are inactive then an autosuspend will be attempted. The attempt may
+ * fail or be delayed.
*
* The caller must hold @udev's device lock.
*
*/
void usb_try_autosuspend_device(struct usb_device *udev)
{
- usb_autopm_do_device(udev, 0);
- dev_vdbg(&udev->dev, "%s: cnt %d\n",
- __func__, udev->pm_usage_cnt);
+ int status;
+
+ status = pm_runtime_idle(&udev->dev);
+ dev_vdbg(&udev->dev, "%s: cnt %d -> %d\n",
+ __func__, atomic_read(&udev->dev.power.usage_count),
+ status);
}
/**
*
* This routine should be called when a core subsystem wants to use @udev
* and needs to guarantee that it is not suspended. No autosuspend will
- * occur until usb_autosuspend_device is called. (Note that this will not
- * prevent suspend events originating in the PM core.) Examples would be
- * when @udev's device file in usbfs is opened or when a remote-wakeup
+ * occur until usb_autosuspend_device() is called. (Note that this will
+ * not prevent suspend events originating in the PM core.) Examples would
+ * be when @udev's device file in usbfs is opened or when a remote-wakeup
* request is received.
*
* @udev's usage counter is incremented to prevent subsequent autosuspends.
{
int status;
- status = usb_autopm_do_device(udev, 1);
- dev_vdbg(&udev->dev, "%s: status %d cnt %d\n",
- __func__, status, udev->pm_usage_cnt);
- return status;
-}
-
-/* Internal routine to adjust an interface's usage counter and change
- * its device's autosuspend state.
- */
-static int usb_autopm_do_interface(struct usb_interface *intf,
- int inc_usage_cnt)
-{
- struct usb_device *udev = interface_to_usbdev(intf);
- int status = 0;
-
- usb_pm_lock(udev);
- if (intf->condition == USB_INTERFACE_UNBOUND)
- status = -ENODEV;
- else {
- atomic_add(inc_usage_cnt, &intf->pm_usage_cnt);
- udev->last_busy = jiffies;
- if (inc_usage_cnt >= 0 &&
- atomic_read(&intf->pm_usage_cnt) > 0) {
- if (udev->state == USB_STATE_SUSPENDED)
- status = usb_resume_both(udev,
- PMSG_AUTO_RESUME);
- if (status != 0)
- atomic_sub(inc_usage_cnt, &intf->pm_usage_cnt);
- else
- udev->last_busy = jiffies;
- } else if (inc_usage_cnt <= 0 &&
- atomic_read(&intf->pm_usage_cnt) <= 0) {
- status = usb_suspend_both(udev, PMSG_AUTO_SUSPEND);
- }
- }
- usb_pm_unlock(udev);
+ status = pm_runtime_get_sync(&udev->dev);
+ if (status < 0)
+ pm_runtime_put_sync(&udev->dev);
+ dev_vdbg(&udev->dev, "%s: cnt %d -> %d\n",
+ __func__, atomic_read(&udev->dev.power.usage_count),
+ status);
+ if (status > 0)
+ status = 0;
return status;
}
* closed.
*
* The routine decrements @intf's usage counter. When the counter reaches
- * 0, a delayed autosuspend request for @intf's device is queued. When
- * the delay expires, if @intf->pm_usage_cnt is still <= 0 along with all
- * the other usage counters for the sibling interfaces and @intf's
- * usb_device, the device and all its interfaces will be autosuspended.
- *
- * Note that @intf->pm_usage_cnt is owned by the interface driver. The
- * core will not change its value other than the increment and decrement
- * in usb_autopm_get_interface and usb_autopm_put_interface. The driver
- * may use this simple counter-oriented discipline or may set the value
- * any way it likes.
+ * 0, a delayed autosuspend request for @intf's device is attempted. The
+ * attempt may fail (see autosuspend_check()).
*
* If the driver has set @intf->needs_remote_wakeup then autosuspend will
* take place only if the device's remote-wakeup facility is enabled.
*
- * Suspend method calls queued by this routine can arrive at any time
- * while @intf is resumed and its usage counter is equal to 0. They are
- * not protected by the usb_device's lock but only by its pm_mutex.
- * Drivers must provide their own synchronization.
- *
* This routine can run only in process context.
*/
void usb_autopm_put_interface(struct usb_interface *intf)
{
- int status;
+ struct usb_device *udev = interface_to_usbdev(intf);
+ int status;
- status = usb_autopm_do_interface(intf, -1);
- dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
- __func__, status, atomic_read(&intf->pm_usage_cnt));
+ udev->last_busy = jiffies;
+ atomic_dec(&intf->pm_usage_cnt);
+ status = pm_runtime_put_sync(&intf->dev);
+ dev_vdbg(&intf->dev, "%s: cnt %d -> %d\n",
+ __func__, atomic_read(&intf->dev.power.usage_count),
+ status);
}
EXPORT_SYMBOL_GPL(usb_autopm_put_interface);
* usb_autopm_put_interface_async - decrement a USB interface's PM-usage counter
* @intf: the usb_interface whose counter should be decremented
*
- * This routine does essentially the same thing as
- * usb_autopm_put_interface(): it decrements @intf's usage counter and
- * queues a delayed autosuspend request if the counter is <= 0. The
- * difference is that it does not acquire the device's pm_mutex;
- * callers must handle all synchronization issues themselves.
+ * This routine does much the same thing as usb_autopm_put_interface():
+ * It decrements @intf's usage counter and schedules a delayed
+ * autosuspend request if the counter is <= 0. The difference is that it
+ * does not perform any synchronization; callers should hold a private
+ * lock and handle all synchronization issues themselves.
*
* Typically a driver would call this routine during an URB's completion
* handler, if no more URBs were pending.
void usb_autopm_put_interface_async(struct usb_interface *intf)
{
struct usb_device *udev = interface_to_usbdev(intf);
+ unsigned long last_busy;
int status = 0;
- if (intf->condition == USB_INTERFACE_UNBOUND) {
- status = -ENODEV;
- } else {
- udev->last_busy = jiffies;
- atomic_dec(&intf->pm_usage_cnt);
- if (udev->autosuspend_disabled || udev->autosuspend_delay < 0)
- status = -EPERM;
- else if (atomic_read(&intf->pm_usage_cnt) <= 0 &&
- !timer_pending(&udev->autosuspend.timer)) {
- queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
+ last_busy = udev->last_busy;
+ udev->last_busy = jiffies;
+ atomic_dec(&intf->pm_usage_cnt);
+ pm_runtime_put_noidle(&intf->dev);
+
+ if (!udev->autosuspend_disabled) {
+ /* Optimization: Don't schedule a delayed autosuspend if
+ * the timer is already running and the expiration time
+ * wouldn't change.
+ *
+ * We have to use the interface's timer. Attempts to
+ * schedule a suspend for the device would fail because
+ * the interface is still active.
+ */
+ if (intf->dev.power.timer_expires == 0 ||
+ round_jiffies_up(last_busy) !=
+ round_jiffies_up(jiffies)) {
+ status = pm_schedule_suspend(&intf->dev,
+ jiffies_to_msecs(
round_jiffies_up_relative(
- udev->autosuspend_delay));
+ udev->autosuspend_delay)));
}
}
- dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
- __func__, status, atomic_read(&intf->pm_usage_cnt));
+ dev_vdbg(&intf->dev, "%s: cnt %d -> %d\n",
+ __func__, atomic_read(&intf->dev.power.usage_count),
+ status);
}
EXPORT_SYMBOL_GPL(usb_autopm_put_interface_async);
/**
+ * usb_autopm_put_interface_no_suspend - decrement a USB interface's PM-usage counter
+ * @intf: the usb_interface whose counter should be decremented
+ *
+ * This routine decrements @intf's usage counter but does not carry out an
+ * autosuspend.
+ *
+ * This routine can run in atomic context.
+ */
+void usb_autopm_put_interface_no_suspend(struct usb_interface *intf)
+{
+ struct usb_device *udev = interface_to_usbdev(intf);
+
+ udev->last_busy = jiffies;
+ atomic_dec(&intf->pm_usage_cnt);
+ pm_runtime_put_noidle(&intf->dev);
+}
+EXPORT_SYMBOL_GPL(usb_autopm_put_interface_no_suspend);
+
+/**
* usb_autopm_get_interface - increment a USB interface's PM-usage counter
* @intf: the usb_interface whose counter should be incremented
*
* or @intf is unbound. A typical example would be a character-device
* driver when its device file is opened.
*
- *
- * The routine increments @intf's usage counter. (However if the
- * autoresume fails then the counter is re-decremented.) So long as the
- * counter is greater than 0, autosuspend will not be allowed for @intf
- * or its usb_device. When the driver is finished using @intf it should
- * call usb_autopm_put_interface() to decrement the usage counter and
- * queue a delayed autosuspend request (if the counter is <= 0).
- *
- *
- * Note that @intf->pm_usage_cnt is owned by the interface driver. The
- * core will not change its value other than the increment and decrement
- * in usb_autopm_get_interface and usb_autopm_put_interface. The driver
- * may use this simple counter-oriented discipline or may set the value
- * any way it likes.
- *
- * Resume method calls generated by this routine can arrive at any time
- * while @intf is suspended. They are not protected by the usb_device's
- * lock but only by its pm_mutex. Drivers must provide their own
- * synchronization.
+ * @intf's usage counter is incremented to prevent subsequent autosuspends.
+ * However if the autoresume fails then the counter is re-decremented.
*
* This routine can run only in process context.
*/
{
int status;
- status = usb_autopm_do_interface(intf, 1);
- dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
- __func__, status, atomic_read(&intf->pm_usage_cnt));
+ status = pm_runtime_get_sync(&intf->dev);
+ if (status < 0)
+ pm_runtime_put_sync(&intf->dev);
+ else
+ atomic_inc(&intf->pm_usage_cnt);
+ dev_vdbg(&intf->dev, "%s: cnt %d -> %d\n",
+ __func__, atomic_read(&intf->dev.power.usage_count),
+ status);
+ if (status > 0)
+ status = 0;
return status;
}
EXPORT_SYMBOL_GPL(usb_autopm_get_interface);
* @intf: the usb_interface whose counter should be incremented
*
* This routine does much the same thing as
- * usb_autopm_get_interface(): it increments @intf's usage counter and
- * queues an autoresume request if the result is > 0. The differences
- * are that it does not acquire the device's pm_mutex (callers must
- * handle all synchronization issues themselves), and it does not
- * autoresume the device directly (it only queues a request). After a
- * successful call, the device will generally not yet be resumed.
+ * usb_autopm_get_interface(): It increments @intf's usage counter and
+ * queues an autoresume request if the device is suspended. The
+ * differences are that it does not perform any synchronization (callers
+ * should hold a private lock and handle all synchronization issues
+ * themselves), and it does not autoresume the device directly (it only
+ * queues a request). After a successful call, the device may not yet be
+ * resumed.
*
* This routine can run in atomic context.
*/
int usb_autopm_get_interface_async(struct usb_interface *intf)
{
- struct usb_device *udev = interface_to_usbdev(intf);
- int status = 0;
+ int status = 0;
+ enum rpm_status s;
- if (intf->condition == USB_INTERFACE_UNBOUND)
- status = -ENODEV;
- else {
+ /* Don't request a resume unless the interface is already suspending
+ * or suspended. Doing so would force a running suspend timer to be
+ * cancelled.
+ */
+ pm_runtime_get_noresume(&intf->dev);
+ s = ACCESS_ONCE(intf->dev.power.runtime_status);
+ if (s == RPM_SUSPENDING || s == RPM_SUSPENDED)
+ status = pm_request_resume(&intf->dev);
+
+ if (status < 0 && status != -EINPROGRESS)
+ pm_runtime_put_noidle(&intf->dev);
+ else
atomic_inc(&intf->pm_usage_cnt);
- if (atomic_read(&intf->pm_usage_cnt) > 0 &&
- udev->state == USB_STATE_SUSPENDED)
- queue_work(ksuspend_usb_wq, &udev->autoresume);
- }
- dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
- __func__, status, atomic_read(&intf->pm_usage_cnt));
+ dev_vdbg(&intf->dev, "%s: cnt %d -> %d\n",
+ __func__, atomic_read(&intf->dev.power.usage_count),
+ status);
+ if (status > 0)
+ status = 0;
return status;
}
EXPORT_SYMBOL_GPL(usb_autopm_get_interface_async);
-#else
+/**
+ * usb_autopm_get_interface_no_resume - increment a USB interface's PM-usage counter
+ * @intf: the usb_interface whose counter should be incremented
+ *
+ * This routine increments @intf's usage counter but does not carry out an
+ * autoresume.
+ *
+ * This routine can run in atomic context.
+ */
+void usb_autopm_get_interface_no_resume(struct usb_interface *intf)
+{
+ struct usb_device *udev = interface_to_usbdev(intf);
+
+ udev->last_busy = jiffies;
+ atomic_inc(&intf->pm_usage_cnt);
+ pm_runtime_get_noresume(&intf->dev);
+}
+EXPORT_SYMBOL_GPL(usb_autopm_get_interface_no_resume);
+
+/* Internal routine to check whether we may autosuspend a device. */
+static int autosuspend_check(struct usb_device *udev)
+{
+ int i;
+ struct usb_interface *intf;
+ unsigned long suspend_time, j;
+
+ /* Fail if autosuspend is disabled, or any interfaces are in use, or
+ * any interface drivers require remote wakeup but it isn't available.
+ */
+ udev->do_remote_wakeup = device_may_wakeup(&udev->dev);
+ if (udev->actconfig) {
+ for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {
+ intf = udev->actconfig->interface[i];
+
+ /* We don't need to check interfaces that are
+ * disabled for runtime PM. Either they are unbound
+ * or else their drivers don't support autosuspend
+ * and so they are permanently active.
+ */
+ if (intf->dev.power.disable_depth)
+ continue;
+ if (atomic_read(&intf->dev.power.usage_count) > 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 or needs remote wakeup.
+ */
+ 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.
+ */
+ j = ACCESS_ONCE(jiffies);
+ suspend_time = udev->last_busy + udev->autosuspend_delay;
+ if (time_before(j, suspend_time)) {
+ pm_schedule_suspend(&udev->dev, jiffies_to_msecs(
+ round_jiffies_up_relative(suspend_time - j)));
+ return -EAGAIN;
+ }
+ return 0;
+}
+
+static int usb_runtime_suspend(struct device *dev)
+{
+ int status = 0;
-void usb_autosuspend_work(struct work_struct *work)
-{}
+ /* A USB device can be suspended if it passes the various autosuspend
+ * checks. Runtime suspend for a USB device means suspending all the
+ * interfaces and then the device itself.
+ */
+ if (is_usb_device(dev)) {
+ struct usb_device *udev = to_usb_device(dev);
+
+ if (autosuspend_check(udev) != 0)
+ return -EAGAIN;
+
+ status = usb_suspend_both(udev, PMSG_AUTO_SUSPEND);
+
+ /* If an interface fails the suspend, adjust the last_busy
+ * time so that we don't get another suspend attempt right
+ * away.
+ */
+ if (status) {
+ udev->last_busy = jiffies +
+ (udev->autosuspend_delay == 0 ?
+ HZ/2 : 0);
+ }
+
+ /* Prevent the parent from suspending immediately after */
+ else if (udev->parent) {
+ udev->parent->last_busy = jiffies;
+ }
+ }
+
+ /* Runtime suspend for a USB interface doesn't mean anything. */
+ return status;
+}
+
+static int usb_runtime_resume(struct device *dev)
+{
+ /* Runtime resume for a USB device means resuming both the device
+ * and all its interfaces.
+ */
+ if (is_usb_device(dev)) {
+ struct usb_device *udev = to_usb_device(dev);
+ int status;
+
+ status = usb_resume_both(udev, PMSG_AUTO_RESUME);
+ udev->last_busy = jiffies;
+ return status;
+ }
+
+ /* Runtime resume for a USB interface doesn't mean anything. */
+ return 0;
+}
+
+static int usb_runtime_idle(struct device *dev)
+{
+ /* An idle USB device can be suspended if it passes the various
+ * autosuspend checks. An idle interface can be suspended at
+ * any time.
+ */
+ if (is_usb_device(dev)) {
+ struct usb_device *udev = to_usb_device(dev);
+
+ if (autosuspend_check(udev) != 0)
+ return 0;
+ }
+
+ pm_runtime_suspend(dev);
+ return 0;
+}
+
+static struct dev_pm_ops usb_bus_pm_ops = {
+ .runtime_suspend = usb_runtime_suspend,
+ .runtime_resume = usb_runtime_resume,
+ .runtime_idle = usb_runtime_idle,
+};
+
+#else
-void usb_autoresume_work(struct work_struct *work)
-{}
+#define usb_bus_pm_ops (*(struct dev_pm_ops *) NULL)
#endif /* CONFIG_USB_SUSPEND */
.name = "usb",
.match = usb_device_match,
.uevent = usb_uevent,
+ .pm = &usb_bus_pm_ops,
};
git://ftp.safe.ca / safe / jmp / linux-2.6 / commitdiff