[PATCH 7/8] PM: Allow USB devices to suspend/resume asynchronously

["Rafael J. Wysocki" <rjw@sisk.pl>]

From: Rafael J. Wysocki <rjw@sisk.pl>

Set power.async_suspend for USB devices, endpoints and interfaces,
allowing them to be suspended and resumed asynchronously during
system sleep transitions.

The power.async_suspend flag is also set for devices that don't have
suspend or resume callbacks, because otherwise they would make the
main suspend/resume thread wait for their "asynchronous" children
(during suspend) or parents (during resume), effectively negating the
possible gains from executing these devices' suspend and resume
callbacks asynchronously.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 drivers/usb/core/endpoint.c |    1 +
 drivers/usb/core/hcd-pci.c  |    1 +
 drivers/usb/core/hub.c      |    1 +
 drivers/usb/core/message.c  |    1 +
 4 files changed, 4 insertions(+)

Index: linux-2.6/drivers/usb/core/hub.c
===================================================================
--- linux-2.6.orig/drivers/usb/core/hub.c
+++ linux-2.6/drivers/usb/core/hub.c
@@ -1817,6 +1817,7 @@ int usb_new_device(struct usb_device *ud
 	/* Tell the world! */
 	announce_device(udev);
 
+	device_enable_async_suspend(&udev->dev);
 	/* Register the device.  The device driver is responsible
 	 * for configuring the device and invoking the add-device
 	 * notifier chain (used by usbfs and possibly others).
Index: linux-2.6/drivers/usb/core/message.c
===================================================================
--- linux-2.6.orig/drivers/usb/core/message.c
+++ linux-2.6/drivers/usb/core/message.c
@@ -1867,6 +1867,7 @@ free_interfaces:
 			"adding %s (config #%d, interface %d)\n",
 			dev_name(&intf->dev), configuration,
 			intf->cur_altsetting->desc.bInterfaceNumber);
+		device_enable_async_suspend(&intf->dev);
 		ret = device_add(&intf->dev);
 		if (ret != 0) {
 			dev_err(&dev->dev, "device_add(%s) --> %d\n",
Index: linux-2.6/drivers/usb/core/endpoint.c
===================================================================
--- linux-2.6.orig/drivers/usb/core/endpoint.c
+++ linux-2.6/drivers/usb/core/endpoint.c
@@ -186,6 +186,7 @@ int usb_create_ep_devs(struct device *pa
 	ep_dev->dev.parent = parent;
 	ep_dev->dev.release = ep_device_release;
 	dev_set_name(&ep_dev->dev, "ep_%02x", endpoint->desc.bEndpointAddress);
+	device_enable_async_suspend(&ep_dev->dev);
 
 	retval = device_register(&ep_dev->dev);
 	if (retval)