Merge branch 'linus' into x86/urgent

[linux-2.6-omap-h63xx.git] / Documentation / ABI / testing / sysfs-bus-usb

diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index f9937add033d833e869fb996565bb74ff2f5233d..11a3c1682cecb87e16514249d6877a18608ccf01 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -39,3 +39,49 @@ Description:
                If you want to suspend a device immediately but leave it
                free to wake up in response to I/O requests, you should
                write "0" to power/autosuspend.
+
+What:          /sys/bus/usb/devices/.../power/persist
+Date:          May 2007
+KernelVersion: 2.6.23
+Contact:       Alan Stern <stern@rowland.harvard.edu>
+Description:
+               If CONFIG_USB_PERSIST is set, then each USB device directory
+               will contain a file named power/persist.  The file holds a
+               boolean value (0 or 1) indicating whether or not the
+               "USB-Persist" facility is enabled for the device.  Since the
+               facility is inherently dangerous, it is disabled by default
+               for all devices except hubs.  For more information, see
+               Documentation/usb/persist.txt.
+
+What:          /sys/bus/usb/device/.../power/connected_duration
+Date:          January 2008
+KernelVersion: 2.6.25
+Contact:       Sarah Sharp <sarah.a.sharp@intel.com>
+Description:
+               If CONFIG_PM and CONFIG_USB_SUSPEND are enabled, then this file
+               is present.  When read, it returns the total time (in msec)
+               that the USB device has been connected to the machine.  This
+               file is read-only.
+Users:
+               PowerTOP <power@bughost.org>
+               http://www.lesswatts.org/projects/powertop/
+
+What:          /sys/bus/usb/device/.../power/active_duration
+Date:          January 2008
+KernelVersion: 2.6.25
+Contact:       Sarah Sharp <sarah.a.sharp@intel.com>
+Description:
+               If CONFIG_PM and CONFIG_USB_SUSPEND are enabled, then this file
+               is present.  When read, it returns the total time (in msec)
+               that the USB device has been active, i.e. not in a suspended
+               state.  This file is read-only.
+
+               Tools can use this file and the connected_duration file to
+               compute the percentage of time that a device has been active.
+               For example,
+               echo $((100 * `cat active_duration` / `cat connected_duration`))
+               will give an integer percentage.  Note that this does not
+               account for counter wrap.
+Users:
+               PowerTOP <power@bughost.org>
+               http://www.lesswatts.org/projects/powertop/