From: Sarah Sharp <[EMAIL PROTECTED]>
This documents two newly created files:
/sys/bus/usb/device/.../power/connected_duration
/sys/bus/usb/device/.../power/active_duration
Documentation was placed in Documentation/ABI/testing, since that's where the
documentation is for the other USB sysfs power files.
Signed-off-by: Sarah Sharp <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
---
Documentation/ABI/testing/sysfs-bus-usb | 33 +++++++++++++++++++++++++++++++
1 files changed, 33 insertions(+), 0 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-usb
b/Documentation/ABI/testing/sysfs-bus-usb
index 9734577..11a3c16 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -52,3 +52,36 @@ Description:
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 <[EMAIL PROTECTED]>
+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 <[EMAIL PROTECTED]>
+ http://www.lesswatts.org/projects/powertop/
+
+What: /sys/bus/usb/device/.../power/active_duration
+Date: January 2008
+KernelVersion: 2.6.25
+Contact: Sarah Sharp <[EMAIL PROTECTED]>
+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 <[EMAIL PROTECTED]>
+ http://www.lesswatts.org/projects/powertop/
--
1.5.3.8
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