+
+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.