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+What: /sys/bus/usb/devices/.../power/autosuspend
+Date: March 2007
+KernelVersion: 2.6.21
+Contact: Alan Stern <stern@rowland.harvard.edu>
+Description:
+ Each USB device directory will contain a file named
+ power/autosuspend. This file holds the time (in seconds)
+ the device must be idle before it will be autosuspended.
+ 0 means the device will be autosuspended as soon as
+ possible. Negative values will prevent the device from
+ being autosuspended at all, and writing a negative value
+ will resume the device if it is already suspended.
+
+ The autosuspend delay for newly-created devices is set to
+ the value of the usbcore.autosuspend module parameter.
+
+What: /sys/bus/usb/devices/.../power/level
+Date: March 2007
+KernelVersion: 2.6.21
+Contact: Alan Stern <stern@rowland.harvard.edu>
+Description:
+ Each USB device directory will contain a file named
+ power/level. This file holds a power-level setting for
+ the device, one of "on", "auto", or "suspend".
+
+ "on" means that the device is not allowed to autosuspend,
+ although normal suspends for system sleep will still
+ be honored. "auto" means the device will autosuspend
+ and autoresume in the usual manner, according to the
+ capabilities of its driver. "suspend" means the device
+ is forced into a suspended state and it will not autoresume
+ in response to I/O requests. However remote-wakeup requests
+ from the device may still be enabled (the remote-wakeup
+ setting is controlled separately by the power/wakeup
+ attribute).
+
+ During normal use, devices should be left in the "auto"
+ level. The other levels are meant for administrative uses.
+ 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.