USB: prepare for changover to Runtime PM framework (8e4ceb38) · Commits · 戴 / test

Documentation/usb/power-management.txt

+28 −32

Original line number	Diff line number	Diff line
		@@ -2,7 +2,7 @@

		Alan Stern <stern@rowland.harvard.edu>

		October 5, 2007
		November 10, 2009



		@@ -123,9 +123,9 @@ relevant attribute files are: wakeup, level, and autosuspend.

		power/level

		This file contains one of three words: "on", "auto",
		or "suspend". You can write those words to the file
		to change the device's setting.
		This file contains one of two words: "on" or "auto".
		You can write those words to the file to change the
		device's setting.

		"on" means that the device should be resumed and
		autosuspend is not allowed. (Of course, system
		@@ -134,10 +134,10 @@ relevant attribute files are: wakeup, level, and autosuspend.
		"auto" is the normal state in which the kernel is
		allowed to autosuspend and autoresume the device.

		"suspend" means that the device should remain
		suspended, and autoresume is not allowed. (But remote
		wakeup may still be allowed, since it is controlled
		separately by the power/wakeup attribute.)
		(In kernels up to 2.6.32, you could also specify
		"suspend", meaning that the device should remain
		suspended and autoresume was not allowed. This
		setting is no longer supported.)

		power/autosuspend

		@@ -313,13 +313,14 @@ three of the methods listed above. In addition, a driver indicates
		that it supports autosuspend by setting the .supports_autosuspend flag
		in its usb_driver structure. It is then responsible for informing the
		USB core whenever one of its interfaces becomes busy or idle. The
		driver does so by calling these five functions:
		driver does so by calling these six functions:

		int usb_autopm_get_interface(struct usb_interface *intf);
		void usb_autopm_put_interface(struct usb_interface *intf);
		int usb_autopm_set_interface(struct usb_interface *intf);
		int usb_autopm_get_interface_async(struct usb_interface *intf);
		void usb_autopm_put_interface_async(struct usb_interface *intf);
		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
		@@ -331,11 +332,13 @@ considered to be idle, and the kernel may autosuspend the device.
		associated with the device itself rather than any of its interfaces.
		This field is used only by the USB core.)

		The driver owns intf->pm_usage_count; it can modify the value however
		and whenever it likes. A nice aspect of the non-async usb_autopm_*
		routines is that the changes they make are protected by the usb_device
		structure's PM mutex (udev->pm_mutex); however drivers may change
		pm_usage_count without holding the mutex. Drivers using the async
		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.

		@@ -347,11 +350,6 @@ exclusion.
		attempts an autosuspend if the new value is <= 0 and the
		device isn't suspended.

		usb_autopm_set_interface() leaves pm_usage_count alone.
		It attempts an autoresume if the value is > 0 and the device
		is suspended, and it attempts an autosuspend if the value is
		<= 0 and the device isn't suspended.

		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
		@@ -360,13 +358,11 @@ exclusion.
		such as an URB's completion handler, but when they return the
		device will not generally not yet be in the desired state.

		There also are a couple of utility routines drivers can use:

		usb_autopm_enable() sets pm_usage_cnt to 0 and then calls
		usb_autopm_set_interface(), which will attempt an autosuspend.

		usb_autopm_disable() sets pm_usage_cnt to 1 and then calls
		usb_autopm_set_interface(), which will attempt an autoresume.
		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.

		The conventional usage pattern is that a driver calls
		usb_autopm_get_interface() in its open routine and
		@@ -400,11 +396,11 @@ 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 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:
		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:

		usb_mark_last_busy(struct usb_device *udev);

drivers/usb/core/driver.c

+0 −31

Original line number	Diff line number	Diff line
		@@ -948,8 +948,6 @@ static int usb_resume_device(struct usb_device *udev, pm_message_t msg)

		done:
		dev_vdbg(&udev->dev, "%s: status %d\n", __func__, status);
		if (status == 0)
		udev->autoresume_disabled = 0;
		return status;
		}

		@@ -1280,11 +1278,6 @@ static int usb_resume_both(struct usb_device *udev, pm_message_t msg)

		/* Propagate the resume up the tree, if necessary */
		if (udev->state == USB_STATE_SUSPENDED) {
		if ((msg.event & PM_EVENT_AUTO) &&
		udev->autoresume_disabled) {
		status = -EPERM;
		goto done;
		}
		if (parent) {
		status = usb_autoresume_device(parent);
		if (status == 0) {
		@@ -1638,8 +1631,6 @@ int usb_autopm_get_interface_async(struct usb_interface *intf)

		if (intf->condition == USB_INTERFACE_UNBOUND)
		status = -ENODEV;
		else if (udev->autoresume_disabled)
		status = -EPERM;
		else {
		atomic_inc(&intf->pm_usage_cnt);
		if (atomic_read(&intf->pm_usage_cnt) > 0 &&
		@@ -1652,28 +1643,6 @@ int usb_autopm_get_interface_async(struct usb_interface *intf)
		}
		EXPORT_SYMBOL_GPL(usb_autopm_get_interface_async);

		/**
		* usb_autopm_set_interface - set a USB interface's autosuspend state
		* @intf: the usb_interface whose state should be set
		*
		* This routine sets the autosuspend state of @intf's device according
		* to @intf's usage counter, which the caller must have set previously.
		* If the counter is <= 0, the device is autosuspended (if it isn't
		* already suspended and if nothing else prevents the autosuspend). If
		* the counter is > 0, the device is autoresumed (if it isn't already
		* awake).
		*/
		int usb_autopm_set_interface(struct usb_interface *intf)
		{
		int status;

		status = usb_autopm_do_interface(intf, 0);
		dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
		__func__, status, atomic_read(&intf->pm_usage_cnt));
		return status;
		}
		EXPORT_SYMBOL_GPL(usb_autopm_set_interface);

		#else

		void usb_autosuspend_work(struct work_struct *work)

drivers/usb/core/hub.c

+32 −13

Original line number	Diff line number	Diff line
		@@ -71,6 +71,7 @@ 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;
		@@ -375,12 +376,13 @@ static void kick_khubd(struct usb_hub *hub)
		{
		unsigned long flags;

		/* Suppress autosuspend until khubd runs */
		atomic_set(&to_usb_interface(hub->intfdev)->pm_usage_cnt, 1);

		spin_lock_irqsave(&hub_event_lock, flags);
		if (!hub->disconnected && list_empty(&hub->event_list)) {
		list_add_tail(&hub->event_list, &hub_event_list);

		/* Suppress autosuspend until khubd runs */
		usb_autopm_get_interface_no_resume(
		to_usb_interface(hub->intfdev));
		wake_up(&khubd_wait);
		}
		spin_unlock_irqrestore(&hub_event_lock, flags);
		@@ -665,7 +667,7 @@ int usb_remove_device(struct usb_device *udev)
		}

		enum hub_activation_type {
		HUB_INIT, HUB_INIT2, HUB_INIT3,
		HUB_INIT, HUB_INIT2, HUB_INIT3, /* INITs must come first */
		HUB_POST_RESET, HUB_RESUME, HUB_RESET_RESUME,
		};

		@@ -710,8 +712,8 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
		msecs_to_jiffies(delay));

		/* Suppress autosuspend until init is done */
		atomic_set(&to_usb_interface(hub->intfdev)->
		pm_usage_cnt, 1);
		usb_autopm_get_interface_no_resume(
		to_usb_interface(hub->intfdev));
		return; /* Continues at init2: below */
		} else {
		hub_power_on(hub, true);
		@@ -818,6 +820,7 @@ 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)
		@@ -827,6 +830,10 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)

		/* Scan all ports that need attention */
		kick_khubd(hub);

		/* Allow autosuspend if it was suppressed */
		if (type <= HUB_INIT3)
		usb_autopm_put_interface_async(to_usb_interface(hub->intfdev));
		}

		/* Implement the continuations for the delays above */
		@@ -854,6 +861,11 @@ 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;
		@@ -1176,7 +1188,10 @@ static void hub_disconnect(struct usb_interface *intf)

		/* Take the hub off the event list and don't let it be added again */
		spin_lock_irq(&hub_event_lock);
		if (!list_empty(&hub->event_list)) {
		list_del_init(&hub->event_list);
		usb_autopm_put_interface_no_suspend(intf);
		}
		hub->disconnected = 1;
		spin_unlock_irq(&hub_event_lock);

		@@ -3235,7 +3250,7 @@ static void hub_events(void)
		* disconnected while waiting for the lock to succeed. */
		usb_lock_device(hdev);
		if (unlikely(hub->disconnected))
		goto loop;
		goto loop2;

		/* If the hub has died, clean up after it */
		if (hdev->state == USB_STATE_NOTATTACHED) {
		@@ -3385,10 +3400,14 @@ static void hub_events(void)
		}

		loop_autopm:
		/* Allow autosuspend if we're not going to run again */
		if (list_empty(&hub->event_list))
		usb_autopm_enable(intf);
		/* Balance the usb_autopm_get_interface() above */
		usb_autopm_put_interface_no_suspend(intf);
		loop:
		/* Balance the usb_autopm_get_interface_no_resume() in
		* kick_khubd() and allow autosuspend.
		*/
		usb_autopm_put_interface(intf);
		loop2:
		usb_unlock_device(hdev);
		kref_put(&hub->kref, hub_release);

drivers/usb/core/sysfs.c

+4 −21

Original line number	Diff line number	Diff line
		@@ -327,7 +327,6 @@ static DEVICE_ATTR(autosuspend, S_IRUGO \| S_IWUSR,

		static const char on_string[] = "on";
		static const char auto_string[] = "auto";
		static const char suspend_string[] = "suspend";

		static ssize_t
		show_level(struct device dev, struct device_attribute attr, char *buf)
		@@ -335,13 +334,8 @@ show_level(struct device dev, struct device_attribute attr, char *buf)
		struct usb_device *udev = to_usb_device(dev);
		const char *p = auto_string;

		if (udev->state == USB_STATE_SUSPENDED) {
		if (udev->autoresume_disabled)
		p = suspend_string;
		} else {
		if (udev->autosuspend_disabled)
		if (udev->state != USB_STATE_SUSPENDED && udev->autosuspend_disabled)
		p = on_string;
		}
		return sprintf(buf, "%s\n", p);
		}

		@@ -353,7 +347,7 @@ set_level(struct device dev, struct device_attribute attr,
		int len = count;
		char *cp;
		int rc = 0;
		int old_autosuspend_disabled, old_autoresume_disabled;
		int old_autosuspend_disabled;

		cp = memchr(buf, '\n', count);
		if (cp)
		@@ -361,7 +355,6 @@ set_level(struct device dev, struct device_attribute attr,

		usb_lock_device(udev);
		old_autosuspend_disabled = udev->autosuspend_disabled;
		old_autoresume_disabled = udev->autoresume_disabled;

		/* Setting the flags without calling usb_pm_lock is a subject to
		* races, but who cares...
		@@ -369,28 +362,18 @@ set_level(struct device dev, struct device_attribute attr,
		if (len == sizeof on_string - 1 &&
		strncmp(buf, on_string, len) == 0) {
		udev->autosuspend_disabled = 1;
		udev->autoresume_disabled = 0;
		rc = usb_external_resume_device(udev, PMSG_USER_RESUME);

		} else if (len == sizeof auto_string - 1 &&
		strncmp(buf, auto_string, len) == 0) {
		udev->autosuspend_disabled = 0;
		udev->autoresume_disabled = 0;
		rc = usb_external_resume_device(udev, PMSG_USER_RESUME);

		} else if (len == sizeof suspend_string - 1 &&
		strncmp(buf, suspend_string, len) == 0) {
		udev->autosuspend_disabled = 0;
		udev->autoresume_disabled = 1;
		rc = usb_external_suspend_device(udev, PMSG_USER_SUSPEND);

		} else
		rc = -EINVAL;

		if (rc) {
		if (rc)
		udev->autosuspend_disabled = old_autosuspend_disabled;
		udev->autoresume_disabled = old_autoresume_disabled;
		}
		usb_unlock_device(udev);
		return (rc < 0 ? rc : count);
		}

include/linux/usb.h

+10 −16

Original line number	Diff line number	Diff line
		@@ -432,7 +432,6 @@ struct usb_tt;
		* @do_remote_wakeup: remote wakeup should be enabled
		* @reset_resume: needs reset instead of resume
		* @autosuspend_disabled: autosuspend disabled by the user
		* @autoresume_disabled: autoresume disabled by the user
		* @skip_sys_resume: skip the next system resume
		* @wusb_dev: if this is a Wireless USB device, link to the WUSB
		* specific data for the device.
		@@ -516,7 +515,6 @@ struct usb_device {
		unsigned do_remote_wakeup:1;
		unsigned reset_resume:1;
		unsigned autosuspend_disabled:1;
		unsigned autoresume_disabled:1;
		unsigned skip_sys_resume:1;
		#endif
		struct wusb_dev *wusb_dev;
		@@ -542,22 +540,20 @@ extern struct usb_device *usb_find_device(u16 vendor_id, u16 product_id);

		/* USB autosuspend and autoresume */
		#ifdef CONFIG_USB_SUSPEND
		extern int usb_autopm_set_interface(struct usb_interface *intf);
		extern int usb_autopm_get_interface(struct usb_interface *intf);
		extern void usb_autopm_put_interface(struct usb_interface *intf);
		extern int usb_autopm_get_interface_async(struct usb_interface *intf);
		extern void usb_autopm_put_interface_async(struct usb_interface *intf);

		static inline void usb_autopm_enable(struct usb_interface *intf)
		static inline void usb_autopm_get_interface_no_resume(
		struct usb_interface *intf)
		{
		atomic_set(&intf->pm_usage_cnt, 0);
		usb_autopm_set_interface(intf);
		atomic_inc(&intf->pm_usage_cnt);
		}

		static inline void usb_autopm_disable(struct usb_interface *intf)
		static inline void usb_autopm_put_interface_no_suspend(
		struct usb_interface *intf)
		{
		atomic_set(&intf->pm_usage_cnt, 1);
		usb_autopm_set_interface(intf);
		atomic_dec(&intf->pm_usage_cnt);
		}

		static inline void usb_mark_last_busy(struct usb_device *udev)
		@@ -567,12 +563,8 @@ static inline void usb_mark_last_busy(struct usb_device *udev)

		#else

		static inline int usb_autopm_set_interface(struct usb_interface *intf)
		{ return 0; }

		static inline int usb_autopm_get_interface(struct usb_interface *intf)
		{ return 0; }

		static inline int usb_autopm_get_interface_async(struct usb_interface *intf)
		{ return 0; }

		@@ -580,9 +572,11 @@ static inline void usb_autopm_put_interface(struct usb_interface *intf)
		{ }
		static inline void usb_autopm_put_interface_async(struct usb_interface *intf)
		{ }
		static inline void usb_autopm_enable(struct usb_interface *intf)
		static inline void usb_autopm_get_interface_no_resume(
		struct usb_interface *intf)
		{ }
		static inline void usb_autopm_disable(struct usb_interface *intf)
		static inline void usb_autopm_put_interface_no_suspend(
		struct usb_interface *intf)
		{ }
		static inline void usb_mark_last_busy(struct usb_device *udev)
		{ }

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