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

From: Rafael J. Wysocki
Date: Sat Jan 23 2010 - 18:45:15 EST


From: Rafael J. Wysocki <rjw@xxxxxxx>

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@xxxxxxx>
---
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)

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