Commit a8e7c565 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
Browse files

usbcore: resume device resume recursion 



This patch (as717b) removes the existing recursion in hub resume code:
Resuming a hub will no longer automatically resume the devices attached
to the hub.

At the same time, it adds one level of recursion: Suspending a USB
device will automatically suspend all the device's interfaces.  Failure
at an intermediate stage will cause all the already-suspended interfaces
to be resumed. Attempts to suspend or resume an interface by itself will
do nothing, although they won't return an error.  Thus the regular
system-suspend and system-resume procedures should continue to work as
before; only runtime PM will be affected.

The patch also removes the code that tests state of the interfaces
before suspending a device.  It's no longer needed, since everything
gets suspended together.


Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 1cc8a25d

drivers/usb/core/driver.c

+55 −8
Original line number Diff line number Diff line
@@ -783,7 +783,7 @@ static int resume_device(struct usb_device *udev) 
	return udriver->resume(udev);

}



/* Caller has locked intf */

/* Caller has locked intf's usb_device */

static int suspend_interface(struct usb_interface *intf, pm_message_t msg)

{

	struct usb_driver	*driver;
@@ -815,7 +815,7 @@ static int suspend_interface(struct usb_interface *intf, pm_message_t msg) 
	return status;

}



/* Caller has locked intf */

/* Caller has locked intf's usb_device */

static int resume_interface(struct usb_interface *intf)

{

	struct usb_driver	*driver;
@@ -856,14 +856,59 @@ static int resume_interface(struct usb_interface *intf) 
	return 0;

}



/* Caller has locked udev */

int usb_suspend_both(struct usb_device *udev, pm_message_t msg)

{

	int			status = 0;

	int			i = 0;

	struct usb_interface	*intf;



	if (udev->actconfig) {

		for (; i < udev->actconfig->desc.bNumInterfaces; i++) {

			intf = udev->actconfig->interface[i];

			status = suspend_interface(intf, msg);

			if (status != 0)

				break;

		}

	}

	if (status == 0)

		status = suspend_device(udev, msg);



	/* If the suspend failed, resume interfaces that did get suspended */

	if (status != 0) {

		while (--i >= 0) {

			intf = udev->actconfig->interface[i];

			resume_interface(intf);

		}

	}

	return status;

}



/* Caller has locked udev */

int usb_resume_both(struct usb_device *udev)

{

	int			status;

	int			i;

	struct usb_interface	*intf;



	status = resume_device(udev);

	if (status == 0 && udev->actconfig) {

		for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {

			intf = udev->actconfig->interface[i];

			resume_interface(intf);

		}

	}

	return status;

}



static int usb_suspend(struct device *dev, pm_message_t message)

{

	int	status;



	if (is_usb_device(dev))

		status = suspend_device(to_usb_device(dev), message);

		status = usb_suspend_both(to_usb_device(dev), message);

	else

		status = suspend_interface(to_usb_interface(dev), message);

		status = 0;

	return status;

}
@@ -871,10 +916,12 @@ static int usb_resume(struct device *dev) 
{

	int	status;



	if (is_usb_device(dev))

		status = resume_device(to_usb_device(dev));

	else

		status = resume_interface(to_usb_interface(dev));

	if (is_usb_device(dev)) {

		status = usb_resume_both(to_usb_device(dev));



		/* Rebind drivers that had no suspend method? */

	} else

		status = 0;

	return status;

}

drivers/usb/core/generic.c

+0 −14
Original line number Diff line number Diff line
@@ -184,22 +184,8 @@ static void generic_disconnect(struct usb_device *udev) 


#ifdef	CONFIG_PM



static int verify_suspended(struct device *dev, void *unused)

{

	if (dev->driver == NULL)

		return 0;

	return (dev->power.power_state.event == PM_EVENT_ON) ? -EBUSY : 0;

}



static int generic_suspend(struct usb_device *udev, pm_message_t msg)

{

	int	status;



	/* rule out bogus requests through sysfs */

	status = device_for_each_child(&udev->dev, NULL, verify_suspended);

	if (status)

		return status;



	/* USB devices enter SUSPEND state through their hubs, but can be

	 * marked for FREEZE as soon as their children are already idled.

	 * But those semantics are useless, so we equate the two (sigh).

drivers/usb/core/hub.c

+13 −83
Original line number Diff line number Diff line
@@ -1662,9 +1662,6 @@ static int finish_port_resume(struct usb_device *udev) 
			"gone after usb resume? status %d\n",

			status);

	else if (udev->actconfig) {

		unsigned	i;

		int		(*resume)(struct device *);



		le16_to_cpus(&devstatus);

		if ((devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP))

				&& udev->parent) {
@@ -1675,24 +1672,9 @@ static int finish_port_resume(struct usb_device *udev) 
					USB_DEVICE_REMOTE_WAKEUP, 0,

					NULL, 0,

					USB_CTRL_SET_TIMEOUT);

			if (status) {

			if (status)

				dev_dbg(&udev->dev, "disable remote "

					"wakeup, status %d\n", status);

				status = 0;

			}

		}



		/* resume interface drivers; if this is a hub, it

		 * may have a child resume event to deal with soon

		 */

		resume = udev->dev.bus->resume;

		for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) {

			struct device *dev =

					&udev->actconfig->interface[i]->dev;



			down(&dev->sem);

			(void) resume(dev);

			up(&dev->sem);

		}

		status = 0;
@@ -1802,15 +1784,7 @@ int usb_port_resume(struct usb_device *udev) 
	} else

		status = finish_port_resume(udev);

	if (status < 0)

		dev_dbg(&udev->dev, "can't resume, status %d\n",

			status);



	/* rebind drivers that had no suspend() */

	if (status == 0) {

		usb_unlock_device(udev);

		bus_rescan_devices(&usb_bus_type);

		usb_lock_device(udev);

	}

		dev_dbg(&udev->dev, "can't resume, status %d\n", status);

	return status;

}
@@ -1830,6 +1804,9 @@ static int remote_wakeup(struct usb_device *udev) 
		msleep(10);

		status = finish_port_resume(udev);

	}



	if (status == 0)

		usb_resume_both(udev);

	usb_unlock_device(udev);

#endif

	return status;
@@ -1901,51 +1878,8 @@ static int hub_resume(struct usb_interface *intf) 
		}

	}



	/* tell khubd to look for changes on this hub */

	hub_activate(hub);



	/* REVISIT:  this recursion probably shouldn't exist.  Remove

	 * this code sometime, after retesting with different root and

	 * external hubs.

	 */

#ifdef	CONFIG_USB_SUSPEND

	{

	unsigned		port1;



	for (port1 = 1; port1 <= hdev->maxchild; port1++) {

		struct usb_device	*udev;

		u16			portstat, portchange;



		udev = hdev->children [port1-1];

		status = hub_port_status(hub, port1, &portstat, &portchange);

		if (status == 0) {

			if (portchange & USB_PORT_STAT_C_SUSPEND) {

				clear_port_feature(hdev, port1,

					USB_PORT_FEAT_C_SUSPEND);

				portchange &= ~USB_PORT_STAT_C_SUSPEND;

			}



			/* let khubd handle disconnects etc */

			if (portchange)

				continue;

		}



		if (!udev || status < 0)

			continue;

		usb_lock_device(udev);

		if (portstat & USB_PORT_STAT_SUSPEND)

			status = hub_port_resume(hub, port1, udev);

		else {

			status = finish_port_resume(udev);

			if (status < 0) {

				dev_dbg(&intf->dev, "resume port %d --> %d\n",

					port1, status);

				hub_port_logical_disconnect(hub, port1);

			}

		}

		usb_unlock_device(udev);

	}

	}

#endif

	return 0;

}
@@ -2602,17 +2536,6 @@ static void hub_events(void) 
		usb_get_intf(intf);

		spin_unlock_irq(&hub_event_lock);



		/* Is this is a root hub wanting to reactivate the downstream

		 * ports?  If so, be sure the interface resumes even if its

		 * stub "device" node was never suspended.

		 */

		if (i) {

			dpm_runtime_resume(&hdev->dev);

			dpm_runtime_resume(&intf->dev);

			usb_put_intf(intf);

			continue;

		}



		/* Lock the device, then check to see if we were

		 * disconnected while waiting for the lock to succeed. */

		if (locktree(hdev) < 0) {
@@ -2629,6 +2552,13 @@ static void hub_events(void) 
			goto loop;

		}



		/* Is this is a root hub wanting to reactivate the downstream

		 * ports?  If so, be sure the interface resumes even if its

		 * stub "device" node was never suspended.

		 */

		if (i)

			usb_resume_both(hdev);



		/* If this is an inactive or suspended hub, do nothing */

		if (hub->quiescing)

			goto loop;

drivers/usb/core/usb.h

+2 −0
Original line number Diff line number Diff line
@@ -30,6 +30,8 @@ extern void usb_major_cleanup(void); 
extern int usb_host_init(void);

extern void usb_host_cleanup(void);



extern int usb_suspend_both(struct usb_device *udev, pm_message_t msg);

extern int usb_resume_both(struct usb_device *udev);

extern int usb_port_suspend(struct usb_device *dev);

extern int usb_port_resume(struct usb_device *dev);

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