2007-03-13 13:39:15 -07:00
|
|
|
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.
|
2007-03-20 11:59:39 -07:00
|
|
|
|
|
|
|
|
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.
|
