diff options
author | Alan Stern <stern@rowland.harvard.edu> | 2010-04-02 13:22:16 -0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-05-20 16:21:37 -0400 |
commit | a90309860b0935805d49e75499fb8dc59fea8e94 (patch) | |
tree | 2d5ed0376a0f0ead945afdaa11be00a48bc0af6c /Documentation/ABI/testing/sysfs-bus-usb | |
parent | 9e18c821659d836bd63f88df3c19729327728496 (diff) |
USB: deprecate the power/level sysfs attribute
This patch (as1367) deprecates USB's power/level sysfs attribute in
favor of the power/control attribute provided by the runtime PM core.
The two attributes do the same thing.
It would be nice to replace power/level with a symlink to
power/control, but at the moment sysfs doesn't offer any way to do so.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'Documentation/ABI/testing/sysfs-bus-usb')
-rw-r--r-- | Documentation/ABI/testing/sysfs-bus-usb | 28 |
1 files changed, 0 insertions, 28 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index bcebb9eaedce..294aa864a60a 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb | |||
@@ -14,34 +14,6 @@ Description: | |||
14 | The autosuspend delay for newly-created devices is set to | 14 | The autosuspend delay for newly-created devices is set to |
15 | the value of the usbcore.autosuspend module parameter. | 15 | the value of the usbcore.autosuspend module parameter. |
16 | 16 | ||
17 | What: /sys/bus/usb/devices/.../power/level | ||
18 | Date: March 2007 | ||
19 | KernelVersion: 2.6.21 | ||
20 | Contact: Alan Stern <stern@rowland.harvard.edu> | ||
21 | Description: | ||
22 | Each USB device directory will contain a file named | ||
23 | power/level. This file holds a power-level setting for | ||
24 | the device, either "on" or "auto". | ||
25 | |||
26 | "on" means that the device is not allowed to autosuspend, | ||
27 | although normal suspends for system sleep will still | ||
28 | be honored. "auto" means the device will autosuspend | ||
29 | and autoresume in the usual manner, according to the | ||
30 | capabilities of its driver. | ||
31 | |||
32 | During normal use, devices should be left in the "auto" | ||
33 | level. The "on" level is meant for administrative uses. | ||
34 | If you want to suspend a device immediately but leave it | ||
35 | free to wake up in response to I/O requests, you should | ||
36 | write "0" to power/autosuspend. | ||
37 | |||
38 | Device not capable of proper suspend and resume should be | ||
39 | left in the "on" level. Although the USB spec requires | ||
40 | devices to support suspend/resume, many of them do not. | ||
41 | In fact so many don't that by default, the USB core | ||
42 | initializes all non-hub devices in the "on" level. Some | ||
43 | drivers may change this setting when they are bound. | ||
44 | |||
45 | What: /sys/bus/usb/devices/.../power/persist | 17 | What: /sys/bus/usb/devices/.../power/persist |
46 | Date: May 2007 | 18 | Date: May 2007 |
47 | KernelVersion: 2.6.23 | 19 | KernelVersion: 2.6.23 |