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Commit | Line | Data |
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eaafbc3a AS |
1 | What: /sys/bus/usb/devices/.../power/autosuspend |
2 | Date: March 2007 | |
3 | KernelVersion: 2.6.21 | |
4 | Contact: Alan Stern <stern@rowland.harvard.edu> | |
5 | Description: | |
6 | Each USB device directory will contain a file named | |
7 | power/autosuspend. This file holds the time (in seconds) | |
8 | the device must be idle before it will be autosuspended. | |
9 | 0 means the device will be autosuspended as soon as | |
10 | possible. Negative values will prevent the device from | |
11 | being autosuspended at all, and writing a negative value | |
12 | will resume the device if it is already suspended. | |
13 | ||
14 | The autosuspend delay for newly-created devices is set to | |
15 | the value of the usbcore.autosuspend module parameter. | |
2add5229 AS |
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 | |
baf67741 | 24 | the device, either "on" or "auto". |
2add5229 AS |
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 | |
baf67741 | 30 | capabilities of its driver. |
2add5229 AS |
31 | |
32 | During normal use, devices should be left in the "auto" | |
baf67741 | 33 | level. The "on" level is meant for administrative uses. |
2add5229 AS |
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. | |
b41a60ec | 37 | |
baf67741 AS |
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 | ||
b41a60ec AS |
45 | What: /sys/bus/usb/devices/.../power/persist |
46 | Date: May 2007 | |
47 | KernelVersion: 2.6.23 | |
48 | Contact: Alan Stern <stern@rowland.harvard.edu> | |
49 | Description: | |
50 | If CONFIG_USB_PERSIST is set, then each USB device directory | |
51 | will contain a file named power/persist. The file holds a | |
52 | boolean value (0 or 1) indicating whether or not the | |
53 | "USB-Persist" facility is enabled for the device. Since the | |
54 | facility is inherently dangerous, it is disabled by default | |
55 | for all devices except hubs. For more information, see | |
56 | Documentation/usb/persist.txt. | |
979e524a SS |
57 | |
58 | What: /sys/bus/usb/device/.../power/connected_duration | |
59 | Date: January 2008 | |
60 | KernelVersion: 2.6.25 | |
61 | Contact: Sarah Sharp <sarah.a.sharp@intel.com> | |
62 | Description: | |
63 | If CONFIG_PM and CONFIG_USB_SUSPEND are enabled, then this file | |
64 | is present. When read, it returns the total time (in msec) | |
65 | that the USB device has been connected to the machine. This | |
66 | file is read-only. | |
67 | Users: | |
68 | PowerTOP <power@bughost.org> | |
69 | http://www.lesswatts.org/projects/powertop/ | |
70 | ||
71 | What: /sys/bus/usb/device/.../power/active_duration | |
72 | Date: January 2008 | |
73 | KernelVersion: 2.6.25 | |
74 | Contact: Sarah Sharp <sarah.a.sharp@intel.com> | |
75 | Description: | |
76 | If CONFIG_PM and CONFIG_USB_SUSPEND are enabled, then this file | |
77 | is present. When read, it returns the total time (in msec) | |
78 | that the USB device has been active, i.e. not in a suspended | |
79 | state. This file is read-only. | |
80 | ||
81 | Tools can use this file and the connected_duration file to | |
82 | compute the percentage of time that a device has been active. | |
83 | For example, | |
84 | echo $((100 * `cat active_duration` / `cat connected_duration`)) | |
85 | will give an integer percentage. Note that this does not | |
86 | account for counter wrap. | |
87 | Users: | |
88 | PowerTOP <power@bughost.org> | |
89 | http://www.lesswatts.org/projects/powertop/ | |
c8cf2465 | 90 | |
49e7cc84 SS |
91 | What: /sys/bus/usb/device/<busnum>-<devnum>...:<config num>-<interface num>/supports_autosuspend |
92 | Date: January 2008 | |
93 | KernelVersion: 2.6.27 | |
94 | Contact: Sarah Sharp <sarah.a.sharp@intel.com> | |
95 | Description: | |
96 | When read, this file returns 1 if the interface driver | |
97 | for this interface supports autosuspend. It also | |
98 | returns 1 if no driver has claimed this interface, as an | |
99 | unclaimed interface will not stop the device from being | |
100 | autosuspended if all other interface drivers are idle. | |
101 | The file returns 0 if autosuspend support has not been | |
102 | added to the driver. | |
103 | Users: | |
104 | USB PM tool | |
105 | git://git.moblin.org/users/sarah/usb-pm-tool/ | |
61e0e79e | 106 | |
c8cf2465 DV |
107 | What: /sys/bus/usb/device/.../authorized |
108 | Date: July 2008 | |
109 | KernelVersion: 2.6.26 | |
110 | Contact: David Vrabel <david.vrabel@csr.com> | |
111 | Description: | |
112 | Authorized devices are available for use by device | |
113 | drivers, non-authorized one are not. By default, wired | |
114 | USB devices are authorized. | |
115 | ||
116 | Certified Wireless USB devices are not authorized | |
117 | initially and should be (by writing 1) after the | |
118 | device has been authenticated. | |
119 | ||
120 | What: /sys/bus/usb/device/.../wusb_cdid | |
121 | Date: July 2008 | |
122 | KernelVersion: 2.6.27 | |
123 | Contact: David Vrabel <david.vrabel@csr.com> | |
124 | Description: | |
125 | For Certified Wireless USB devices only. | |
126 | ||
127 | A devices's CDID, as 16 space-separated hex octets. | |
128 | ||
129 | What: /sys/bus/usb/device/.../wusb_ck | |
130 | Date: July 2008 | |
131 | KernelVersion: 2.6.27 | |
132 | Contact: David Vrabel <david.vrabel@csr.com> | |
133 | Description: | |
134 | For Certified Wireless USB devices only. | |
135 | ||
136 | Write the device's connection key (CK) to start the | |
137 | authentication of the device. The CK is 16 | |
138 | space-separated hex octets. | |
139 | ||
140 | What: /sys/bus/usb/device/.../wusb_disconnect | |
141 | Date: July 2008 | |
142 | KernelVersion: 2.6.27 | |
143 | Contact: David Vrabel <david.vrabel@csr.com> | |
144 | Description: | |
145 | For Certified Wireless USB devices only. | |
146 | ||
147 | Write a 1 to force the device to disconnect | |
148 | (equivalent to unplugging a wired USB device). | |
0c7a2b72 CR |
149 | |
150 | What: /sys/bus/usb/drivers/.../remove_id | |
151 | Date: November 2009 | |
152 | Contact: CHENG Renquan <rqcheng@smu.edu.sg> | |
153 | Description: | |
154 | Writing a device ID to this file will remove an ID | |
155 | that was dynamically added via the new_id sysfs entry. | |
156 | The format for the device ID is: | |
157 | idVendor idProduct. After successfully | |
158 | removing an ID, the driver will no longer support the | |
159 | device. This is useful to ensure auto probing won't | |
160 | match the driver to the device. For example: | |
161 | # echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id | |
ef955341 | 162 | |
1e63ef0e | 163 | What: /sys/bus/usb/device/.../avoid_reset_quirk |
ef955341 ON |
164 | Date: December 2009 |
165 | Contact: Oliver Neukum <oliver@neukum.org> | |
166 | Description: | |
167 | Writing 1 to this file tells the kernel that this | |
168 | device will morph into another mode when it is reset. | |
169 | Drivers will not use reset for error handling for | |
170 | such devices. | |
171 | Users: | |
172 | usb_modeswitch |