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Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-usb | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index 00a84326325f..f9937add033d 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -13,3 +13,29 @@ Description: 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. |