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-rw-r--r--Documentation/ABI/testing/sysfs-bus-usb15
1 files changed, 15 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index 294aa864a60..e647378e9e8 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.