USB: implement usb_enable_autosuspend

This patch (as1326) adds usb_enable_autosuspend() and
usb_disable_autosuspend() routines for use by drivers.  If a driver
knows that its device can handle suspends and resumes correctly, it
can enable autosuspend all by itself.  This is equivalent to the user
writing "auto" to the device's power/level attribute.

The implementation differs slightly from what it used to be.  Now
autosuspend is disabled simply by doing usb_autoresume_device() (to
increment the usage counter) and enabled by doing
usb_autosuspend_device() (to decrement the usage counter).

The set_level() attribute method is updated to use the new routines,
and the USB Power-Management documentation is updated.

The patch adds a usb_enable_autosuspend() call to the hub driver's
probe routine, allowing the special-case code for hubs in quirks.c to
be removed.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 4 insertions, 5 deletions

diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
index 0b689224394b..4314f259524b 100644
--- a/drivers/usb/core/quirks.c
+++ b/drivers/usb/core/quirks.c
@@ -103,11 +103,10 @@ void usb_detect_quirks(struct usb_device *udev)
                 dev_dbg(&udev->dev, "USB quirks for this device: %x\n",
                                 udev->quirks);
 
-        /* By default, disable autosuspend for all non-hubs */
-#ifdef  CONFIG_USB_SUSPEND
-        if (udev->descriptor.bDeviceClass != USB_CLASS_HUB)
-                udev->autosuspend_disabled = 1;
-#endif
+        /* By default, disable autosuspend for all devices.  The hub driver
+         * will enable it for hubs.
+         */
+        usb_disable_autosuspend(udev);
 
         /* For the present, all devices default to USB-PERSIST enabled */
 #if 0           /* was: #ifdef CONFIG_PM */