Commit | Line | Data |
---|---|---|
971cb7fb RW |
1 | What: /sys/devices/.../power/ |
2 | Date: January 2009 | |
49db1903 | 3 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
971cb7fb RW |
4 | Description: |
5 | The /sys/devices/.../power directory contains attributes | |
6 | allowing the user space to check and modify some power | |
7 | management related properties of given device. | |
8 | ||
9 | What: /sys/devices/.../power/wakeup | |
10 | Date: January 2009 | |
49db1903 | 11 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
971cb7fb RW |
12 | Description: |
13 | The /sys/devices/.../power/wakeup attribute allows the user | |
14 | space to check if the device is enabled to wake up the system | |
15 | from sleep states, such as the memory sleep state (suspend to | |
16 | RAM) and hibernation (suspend to disk), and to enable or disable | |
17 | it to do that as desired. | |
18 | ||
19 | Some devices support "wakeup" events, which are hardware signals | |
20 | used to activate the system from a sleep state. Such devices | |
21 | have one of the following two values for the sysfs power/wakeup | |
22 | file: | |
23 | ||
24 | + "enabled\n" to issue the events; | |
25 | + "disabled\n" not to do so; | |
26 | ||
27 | In that cases the user space can change the setting represented | |
28 | by the contents of this file by writing either "enabled", or | |
29 | "disabled" to it. | |
30 | ||
31 | For the devices that are not capable of generating system wakeup | |
cb8f51bd RW |
32 | events this file is not present. In that case the device cannot |
33 | be enabled to wake up the system from sleep states. | |
971cb7fb RW |
34 | |
35 | What: /sys/devices/.../power/control | |
36 | Date: January 2009 | |
49db1903 | 37 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
971cb7fb RW |
38 | Description: |
39 | The /sys/devices/.../power/control attribute allows the user | |
40 | space to control the run-time power management of the device. | |
41 | ||
42 | All devices have one of the following two values for the | |
43 | power/control file: | |
44 | ||
45 | + "auto\n" to allow the device to be power managed at run time; | |
46 | + "on\n" to prevent the device from being power managed; | |
47 | ||
48 | The default for all devices is "auto", which means that they may | |
49 | be subject to automatic power management, depending on their | |
50 | drivers. Changing this attribute to "on" prevents the driver | |
51 | from power managing the device at run time. Doing that while | |
52 | the device is suspended causes it to be woken up. | |
5a2eb858 RW |
53 | |
54 | What: /sys/devices/.../power/async | |
55 | Date: January 2009 | |
49db1903 | 56 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
5a2eb858 RW |
57 | Description: |
58 | The /sys/devices/.../async attribute allows the user space to | |
59 | enable or diasble the device's suspend and resume callbacks to | |
60 | be executed asynchronously (ie. in separate threads, in parallel | |
61 | with the main suspend/resume thread) during system-wide power | |
62 | transitions (eg. suspend to RAM, hibernation). | |
63 | ||
64 | All devices have one of the following two values for the | |
65 | power/async file: | |
66 | ||
67 | + "enabled\n" to permit the asynchronous suspend/resume; | |
68 | + "disabled\n" to forbid it; | |
69 | ||
70 | The value of this attribute may be changed by writing either | |
71 | "enabled", or "disabled" to it. | |
72 | ||
73 | It generally is unsafe to permit the asynchronous suspend/resume | |
74 | of a device unless it is certain that all of the PM dependencies | |
75 | of the device are known to the PM core. However, for some | |
76 | devices this attribute is set to "enabled" by bus type code or | |
77 | device drivers and in that cases it should be safe to leave the | |
78 | default value. | |
074037ec RW |
79 | |
80 | What: /sys/devices/.../power/wakeup_count | |
81 | Date: September 2010 | |
49db1903 | 82 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
074037ec RW |
83 | Description: |
84 | The /sys/devices/.../wakeup_count attribute contains the number | |
85 | of signaled wakeup events associated with the device. This | |
86 | attribute is read-only. If the device is not enabled to wake up | |
cb8f51bd | 87 | the system from sleep states, this attribute is not present. |
074037ec RW |
88 | |
89 | What: /sys/devices/.../power/wakeup_active_count | |
90 | Date: September 2010 | |
49db1903 | 91 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
074037ec RW |
92 | Description: |
93 | The /sys/devices/.../wakeup_active_count attribute contains the | |
94 | number of times the processing of wakeup events associated with | |
95 | the device was completed (at the kernel level). This attribute | |
96 | is read-only. If the device is not enabled to wake up the | |
cb8f51bd | 97 | system from sleep states, this attribute is not present. |
074037ec | 98 | |
30e3ce6d RW |
99 | What: /sys/devices/.../power/wakeup_abort_count |
100 | Date: February 2012 | |
49db1903 | 101 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
074037ec | 102 | Description: |
30e3ce6d | 103 | The /sys/devices/.../wakeup_abort_count attribute contains the |
074037ec | 104 | number of times the processing of a wakeup event associated with |
30e3ce6d RW |
105 | the device might have aborted system transition into a sleep |
106 | state in progress. This attribute is read-only. If the device | |
107 | is not enabled to wake up the system from sleep states, this | |
108 | attribute is not present. | |
109 | ||
110 | What: /sys/devices/.../power/wakeup_expire_count | |
111 | Date: February 2012 | |
49db1903 | 112 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
30e3ce6d RW |
113 | Description: |
114 | The /sys/devices/.../wakeup_expire_count attribute contains the | |
115 | number of times a wakeup event associated with the device has | |
116 | been reported with a timeout that expired. This attribute is | |
117 | read-only. If the device is not enabled to wake up the system | |
118 | from sleep states, this attribute is not present. | |
074037ec RW |
119 | |
120 | What: /sys/devices/.../power/wakeup_active | |
121 | Date: September 2010 | |
49db1903 | 122 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
074037ec RW |
123 | Description: |
124 | The /sys/devices/.../wakeup_active attribute contains either 1, | |
125 | or 0, depending on whether or not a wakeup event associated with | |
126 | the device is being processed (1). This attribute is read-only. | |
127 | If the device is not enabled to wake up the system from sleep | |
cb8f51bd | 128 | states, this attribute is not present. |
074037ec RW |
129 | |
130 | What: /sys/devices/.../power/wakeup_total_time_ms | |
131 | Date: September 2010 | |
49db1903 | 132 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
074037ec RW |
133 | Description: |
134 | The /sys/devices/.../wakeup_total_time_ms attribute contains | |
135 | the total time of processing wakeup events associated with the | |
136 | device, in milliseconds. This attribute is read-only. If the | |
137 | device is not enabled to wake up the system from sleep states, | |
cb8f51bd | 138 | this attribute is not present. |
074037ec RW |
139 | |
140 | What: /sys/devices/.../power/wakeup_max_time_ms | |
141 | Date: September 2010 | |
49db1903 | 142 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
074037ec RW |
143 | Description: |
144 | The /sys/devices/.../wakeup_max_time_ms attribute contains | |
145 | the maximum time of processing a single wakeup event associated | |
146 | with the device, in milliseconds. This attribute is read-only. | |
147 | If the device is not enabled to wake up the system from sleep | |
cb8f51bd | 148 | states, this attribute is not present. |
074037ec RW |
149 | |
150 | What: /sys/devices/.../power/wakeup_last_time_ms | |
151 | Date: September 2010 | |
49db1903 | 152 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
074037ec RW |
153 | Description: |
154 | The /sys/devices/.../wakeup_last_time_ms attribute contains | |
155 | the value of the monotonic clock corresponding to the time of | |
156 | signaling the last wakeup event associated with the device, in | |
157 | milliseconds. This attribute is read-only. If the device is | |
158 | not enabled to wake up the system from sleep states, this | |
cb8f51bd | 159 | attribute is not present. |
15bcb91d | 160 | |
55850945 RW |
161 | What: /sys/devices/.../power/wakeup_prevent_sleep_time_ms |
162 | Date: February 2012 | |
49db1903 | 163 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
55850945 RW |
164 | Description: |
165 | The /sys/devices/.../wakeup_prevent_sleep_time_ms attribute | |
166 | contains the total time the device has been preventing | |
4e79162a | 167 | opportunistic transitions to sleep states from occurring. |
55850945 RW |
168 | This attribute is read-only. If the device is not enabled to |
169 | wake up the system from sleep states, this attribute is not | |
170 | present. | |
171 | ||
15bcb91d AS |
172 | What: /sys/devices/.../power/autosuspend_delay_ms |
173 | Date: September 2010 | |
174 | Contact: Alan Stern <stern@rowland.harvard.edu> | |
175 | Description: | |
176 | The /sys/devices/.../power/autosuspend_delay_ms attribute | |
177 | contains the autosuspend delay value (in milliseconds). Some | |
178 | drivers do not want their device to suspend as soon as it | |
179 | becomes idle at run time; they want the device to remain | |
180 | inactive for a certain minimum period of time first. That | |
181 | period is called the autosuspend delay. Negative values will | |
182 | prevent the device from being suspended at run time (similar | |
183 | to writing "on" to the power/control attribute). Values >= | |
184 | 1000 will cause the autosuspend timer expiration to be rounded | |
185 | up to the nearest second. | |
186 | ||
187 | Not all drivers support this attribute. If it isn't supported, | |
188 | attempts to read or write it will yield I/O errors. | |
85dc0b8a RW |
189 | |
190 | What: /sys/devices/.../power/pm_qos_latency_us | |
191 | Date: March 2012 | |
49db1903 | 192 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
85dc0b8a RW |
193 | Description: |
194 | The /sys/devices/.../power/pm_qos_resume_latency_us attribute | |
195 | contains the PM QoS resume latency limit for the given device, | |
196 | which is the maximum allowed time it can take to resume the | |
197 | device, after it has been suspended at run time, from a resume | |
198 | request to the moment the device will be ready to process I/O, | |
199 | in microseconds. If it is equal to 0, however, this means that | |
200 | the PM QoS resume latency may be arbitrary. | |
201 | ||
202 | Not all drivers support this attribute. If it isn't supported, | |
203 | it is not present. | |
204 | ||
205 | This attribute has no effect on system-wide suspend/resume and | |
206 | hibernation. | |
e39473d0 RW |
207 | |
208 | What: /sys/devices/.../power/pm_qos_no_power_off | |
209 | Date: September 2012 | |
49db1903 | 210 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
e39473d0 RW |
211 | Description: |
212 | The /sys/devices/.../power/pm_qos_no_power_off attribute | |
213 | is used for manipulating the PM QoS "no power off" flag. If | |
214 | set, this flag indicates to the kernel that power should not | |
215 | be removed entirely from the device. | |
216 | ||
217 | Not all drivers support this attribute. If it isn't supported, | |
218 | it is not present. | |
219 | ||
220 | This attribute has no effect on system-wide suspend/resume and | |
221 | hibernation. | |
222 | ||
223 | What: /sys/devices/.../power/pm_qos_remote_wakeup | |
224 | Date: September 2012 | |
49db1903 | 225 | Contact: Rafael J. Wysocki <rjw@rjwysocki.net> |
e39473d0 RW |
226 | Description: |
227 | The /sys/devices/.../power/pm_qos_remote_wakeup attribute | |
228 | is used for manipulating the PM QoS "remote wakeup required" | |
229 | flag. If set, this flag indicates to the kernel that the | |
230 | device is a source of user events that have to be signaled from | |
231 | its low-power states. | |
232 | ||
233 | Not all drivers support this attribute. If it isn't supported, | |
234 | it is not present. | |
235 | ||
236 | This attribute has no effect on system-wide suspend/resume and | |
237 | hibernation. |