USB: Export if an interface driver supports autosuspend.

Create a new sysfs file per interface named supports_autosuspend.  This
file returns true if an interface driver's .supports_autosuspend flag is
set.  It also returns true if the interface is unclaimed (since the USB
core will autosuspend a device if an interface is not claimed).

This new sysfs file will be useful for user space scripts to test whether
a USB device correctly auto-suspends.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 16 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index 11a3c1682cec..df6c8a0159f1 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -85,3 +85,19 @@ Description:
 Users:
                 PowerTOP <power@bughost.org>
                 http://www.lesswatts.org/projects/powertop/
+
+What:           /sys/bus/usb/device/<busnum>-<devnum>...:<config num>-<interface num>/supports_autosuspend
+Date:           January 2008
+KernelVersion:  2.6.27
+Contact:        Sarah Sharp <sarah.a.sharp@intel.com>
+Description:
+                When read, this file returns 1 if the interface driver
+                for this interface supports autosuspend.  It also
+                returns 1 if no driver has claimed this interface, as an
+                unclaimed interface will not stop the device from being
+                autosuspended if all other interface drivers are idle.
+                The file returns 0 if autosuspend support has not been
+                added to the driver.
+Users:
+                USB PM tool
+                git://git.moblin.org/users/sarah/usb-pm-tool/