PM: Allow USB devices to suspend/resume asynchronously

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>

3 files changed, 3 insertions, 0 deletions

diff --git a/drivers/usb/core/endpoint.c b/drivers/usb/core/endpoint.c
index fdfaa7885515..d26b9ea981f9 100644
--- a/drivers/usb/core/endpoint.c
+++ b/drivers/usb/core/endpoint.c
@@ -186,6 +186,7 @@ int usb_create_ep_devs(struct device *parent,
         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)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 35cc8b9ba1f5..20ecb4cec8de 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1817,6 +1817,7 @@ int usb_new_device(struct usb_device *udev)
         /* 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).
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 9bc95fec793f..df73574a9cc9 100644
--- a/drivers/usb/core/message.c
+++ b/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",