diff options
Diffstat (limited to 'Documentation/ABI/testing/sysfs-bus-usb')
-rw-r--r-- | Documentation/ABI/testing/sysfs-bus-usb | 39 |
1 files changed, 11 insertions, 28 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index a07c0f366f91..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 |
@@ -159,3 +131,14 @@ Description: | |||
159 | device. This is useful to ensure auto probing won't | 131 | device. This is useful to ensure auto probing won't |
160 | match the driver to the device. For example: | 132 | match the driver to the device. For example: |
161 | # echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id | 133 | # echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id |
134 | |||
135 | What: /sys/bus/usb/device/.../avoid_reset_quirk | ||
136 | Date: December 2009 | ||
137 | Contact: Oliver Neukum <oliver@neukum.org> | ||
138 | Description: | ||
139 | Writing 1 to this file tells the kernel that this | ||
140 | device will morph into another mode when it is reset. | ||
141 | Drivers will not use reset for error handling for | ||
142 | such devices. | ||
143 | Users: | ||
144 | usb_modeswitch | ||