1 files changed, 15 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index 294aa864a60a..e647378e9e88 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -142,3 +142,18 @@ Description:
                 such devices.
 Users:
                 usb_modeswitch
+
+What:           /sys/bus/usb/devices/.../power/usb2_hardware_lpm
+Date:           September 2011
+Contact:        Andiry Xu <andiry.xu@amd.com>
+Description:
+                If CONFIG_USB_SUSPEND is set and a USB 2.0 lpm-capable device
+                is plugged in to a xHCI host which support link PM, it will
+                perform a LPM test; if the test is passed and host supports
+                USB2 hardware LPM (xHCI 1.0 feature), USB2 hardware LPM will
+                be enabled for the device and the USB device directory will
+                contain a file named power/usb2_hardware_lpm.  The file holds
+                a string value (enable or disable) indicating whether or not
+                USB2 hardware LPM is enabled for the device. Developer can
+                write y/Y/1 or n/N/0 to the file to enable/disable the
+                feature.