1 What: /sys/devices/.../power/ 1 What: /sys/devices/.../power/
2 Date: January 2009 2 Date: January 2009
3 Contact: Rafael J. Wysocki <rjw@rjwysock !! 3 Contact: Rafael J. Wysocki <rjw@sisk.pl>
4 Description: 4 Description:
5 The /sys/devices/.../power dir 5 The /sys/devices/.../power directory contains attributes
6 allowing the user space to che 6 allowing the user space to check and modify some power
7 management related properties 7 management related properties of given device.
8 8
9 What: /sys/devices/.../power/wakeup 9 What: /sys/devices/.../power/wakeup
10 Date: January 2009 10 Date: January 2009
11 Contact: Rafael J. Wysocki <rjw@rjwysock !! 11 Contact: Rafael J. Wysocki <rjw@sisk.pl>
12 Description: 12 Description:
13 The /sys/devices/.../power/wak 13 The /sys/devices/.../power/wakeup attribute allows the user
14 space to check if the device i 14 space to check if the device is enabled to wake up the system
15 from sleep states, such as the 15 from sleep states, such as the memory sleep state (suspend to
16 RAM) and hibernation (suspend 16 RAM) and hibernation (suspend to disk), and to enable or disable
17 it to do that as desired. 17 it to do that as desired.
18 18
19 Some devices support "wakeup" 19 Some devices support "wakeup" events, which are hardware signals
20 used to activate the system fr 20 used to activate the system from a sleep state. Such devices
21 have one of the following two 21 have one of the following two values for the sysfs power/wakeup
22 file: 22 file:
23 23
24 + "enabled\n" to issue the eve 24 + "enabled\n" to issue the events;
25 + "disabled\n" not to do so; 25 + "disabled\n" not to do so;
26 26
27 In that cases the user space c 27 In that cases the user space can change the setting represented
28 by the contents of this file b 28 by the contents of this file by writing either "enabled", or
29 "disabled" to it. 29 "disabled" to it.
30 30
31 For the devices that are not c 31 For the devices that are not capable of generating system wakeup
32 events this file is not presen 32 events this file is not present. In that case the device cannot
33 be enabled to wake up the syst 33 be enabled to wake up the system from sleep states.
34 34
35 What: /sys/devices/.../power/control 35 What: /sys/devices/.../power/control
36 Date: January 2009 36 Date: January 2009
37 Contact: Rafael J. Wysocki <rjw@rjwysock !! 37 Contact: Rafael J. Wysocki <rjw@sisk.pl>
38 Description: 38 Description:
39 The /sys/devices/.../power/con 39 The /sys/devices/.../power/control attribute allows the user
40 space to control the run-time 40 space to control the run-time power management of the device.
41 41
42 All devices have one of the fo 42 All devices have one of the following two values for the
43 power/control file: 43 power/control file:
44 44
45 + "auto\n" to allow the device 45 + "auto\n" to allow the device to be power managed at run time;
46 + "on\n" to prevent the device 46 + "on\n" to prevent the device from being power managed;
47 47
48 The default for all devices is 48 The default for all devices is "auto", which means that they may
49 be subject to automatic power 49 be subject to automatic power management, depending on their
50 drivers. Changing this attrib 50 drivers. Changing this attribute to "on" prevents the driver
51 from power managing the device 51 from power managing the device at run time. Doing that while
52 the device is suspended causes 52 the device is suspended causes it to be woken up.
53 53
54 What: /sys/devices/.../power/async 54 What: /sys/devices/.../power/async
55 Date: January 2009 55 Date: January 2009
56 Contact: Rafael J. Wysocki <rjw@rjwysock !! 56 Contact: Rafael J. Wysocki <rjw@sisk.pl>
57 Description: 57 Description:
58 The /sys/devices/.../async att 58 The /sys/devices/.../async attribute allows the user space to
59 enable or diasble the device's 59 enable or diasble the device's suspend and resume callbacks to
60 be executed asynchronously (ie 60 be executed asynchronously (ie. in separate threads, in parallel
61 with the main suspend/resume t 61 with the main suspend/resume thread) during system-wide power
62 transitions (eg. suspend to RA 62 transitions (eg. suspend to RAM, hibernation).
63 63
64 All devices have one of the fo 64 All devices have one of the following two values for the
65 power/async file: 65 power/async file:
66 66
67 + "enabled\n" to permit the as 67 + "enabled\n" to permit the asynchronous suspend/resume;
68 + "disabled\n" to forbid it; 68 + "disabled\n" to forbid it;
69 69
70 The value of this attribute ma 70 The value of this attribute may be changed by writing either
71 "enabled", or "disabled" to it 71 "enabled", or "disabled" to it.
72 72
73 It generally is unsafe to perm 73 It generally is unsafe to permit the asynchronous suspend/resume
74 of a device unless it is certa 74 of a device unless it is certain that all of the PM dependencies
75 of the device are known to the 75 of the device are known to the PM core. However, for some
76 devices this attribute is set 76 devices this attribute is set to "enabled" by bus type code or
77 device drivers and in that cas 77 device drivers and in that cases it should be safe to leave the
78 default value. 78 default value.
79 79
80 What: /sys/devices/.../power/wakeup_ 80 What: /sys/devices/.../power/wakeup_count
81 Date: September 2010 81 Date: September 2010
82 Contact: Rafael J. Wysocki <rjw@rjwysock !! 82 Contact: Rafael J. Wysocki <rjw@sisk.pl>
83 Description: 83 Description:
84 The /sys/devices/.../wakeup_co 84 The /sys/devices/.../wakeup_count attribute contains the number
85 of signaled wakeup events asso 85 of signaled wakeup events associated with the device. This
86 attribute is read-only. If th !! 86 attribute is read-only. If the device is not enabled to wake up
87 the system from sleep states, 87 the system from sleep states, this attribute is not present.
88 If the device is not enabled t <<
89 states, this attribute is empt <<
90 88
91 What: /sys/devices/.../power/wakeup_ 89 What: /sys/devices/.../power/wakeup_active_count
92 Date: September 2010 90 Date: September 2010
93 Contact: Rafael J. Wysocki <rjw@rjwysock !! 91 Contact: Rafael J. Wysocki <rjw@sisk.pl>
94 Description: 92 Description:
95 The /sys/devices/.../wakeup_ac 93 The /sys/devices/.../wakeup_active_count attribute contains the
96 number of times the processing 94 number of times the processing of wakeup events associated with
97 the device was completed (at t 95 the device was completed (at the kernel level). This attribute
98 is read-only. If the device i !! 96 is read-only. If the device is not enabled to wake up the
99 system from sleep states, this !! 97 system from sleep states, this attribute is not present.
100 the device is not enabled to w <<
101 states, this attribute is empt <<
102 98
103 What: /sys/devices/.../power/wakeup_ 99 What: /sys/devices/.../power/wakeup_abort_count
104 Date: February 2012 100 Date: February 2012
105 Contact: Rafael J. Wysocki <rjw@rjwysock !! 101 Contact: Rafael J. Wysocki <rjw@sisk.pl>
106 Description: 102 Description:
107 The /sys/devices/.../wakeup_ab 103 The /sys/devices/.../wakeup_abort_count attribute contains the
108 number of times the processing 104 number of times the processing of a wakeup event associated with
109 the device might have aborted 105 the device might have aborted system transition into a sleep
110 state in progress. This attri 106 state in progress. This attribute is read-only. If the device
111 is not capable to wake up the !! 107 is not enabled to wake up the system from sleep states, this
112 attribute is not present. If !! 108 attribute is not present.
113 up the system from sleep state <<
114 109
115 What: /sys/devices/.../power/wakeup_ 110 What: /sys/devices/.../power/wakeup_expire_count
116 Date: February 2012 111 Date: February 2012
117 Contact: Rafael J. Wysocki <rjw@rjwysock !! 112 Contact: Rafael J. Wysocki <rjw@sisk.pl>
118 Description: 113 Description:
119 The /sys/devices/.../wakeup_ex 114 The /sys/devices/.../wakeup_expire_count attribute contains the
120 number of times a wakeup event 115 number of times a wakeup event associated with the device has
121 been reported with a timeout t 116 been reported with a timeout that expired. This attribute is
122 read-only. If the device is n !! 117 read-only. If the device is not enabled to wake up the system
123 from sleep states, this attrib !! 118 from sleep states, this attribute is not present.
124 device is not enabled to wake <<
125 this attribute is empty. <<
126 119
127 What: /sys/devices/.../power/wakeup_ 120 What: /sys/devices/.../power/wakeup_active
128 Date: September 2010 121 Date: September 2010
129 Contact: Rafael J. Wysocki <rjw@rjwysock !! 122 Contact: Rafael J. Wysocki <rjw@sisk.pl>
130 Description: 123 Description:
131 The /sys/devices/.../wakeup_ac 124 The /sys/devices/.../wakeup_active attribute contains either 1,
132 or 0, depending on whether or 125 or 0, depending on whether or not a wakeup event associated with
133 the device is being processed 126 the device is being processed (1). This attribute is read-only.
134 If the device is not capable t !! 127 If the device is not enabled to wake up the system from sleep
135 states, this attribute is not !! 128 states, this attribute is not present.
136 enabled to wake up the system <<
137 is empty. <<
138 129
139 What: /sys/devices/.../power/wakeup_ 130 What: /sys/devices/.../power/wakeup_total_time_ms
140 Date: September 2010 131 Date: September 2010
141 Contact: Rafael J. Wysocki <rjw@rjwysock !! 132 Contact: Rafael J. Wysocki <rjw@sisk.pl>
142 Description: 133 Description:
143 The /sys/devices/.../wakeup_to 134 The /sys/devices/.../wakeup_total_time_ms attribute contains
144 the total time of processing w 135 the total time of processing wakeup events associated with the
145 device, in milliseconds. This 136 device, in milliseconds. This attribute is read-only. If the
146 device is not capable to wake !! 137 device is not enabled to wake up the system from sleep states,
147 this attribute is not present. !! 138 this attribute is not present.
148 wake up the system from sleep <<
149 139
150 What: /sys/devices/.../power/wakeup_ 140 What: /sys/devices/.../power/wakeup_max_time_ms
151 Date: September 2010 141 Date: September 2010
152 Contact: Rafael J. Wysocki <rjw@rjwysock !! 142 Contact: Rafael J. Wysocki <rjw@sisk.pl>
153 Description: 143 Description:
154 The /sys/devices/.../wakeup_ma 144 The /sys/devices/.../wakeup_max_time_ms attribute contains
155 the maximum time of processing 145 the maximum time of processing a single wakeup event associated
156 with the device, in millisecon 146 with the device, in milliseconds. This attribute is read-only.
157 If the device is not capable t !! 147 If the device is not enabled to wake up the system from sleep
158 states, this attribute is not !! 148 states, this attribute is not present.
159 enabled to wake up the system <<
160 is empty. <<
161 149
162 What: /sys/devices/.../power/wakeup_ 150 What: /sys/devices/.../power/wakeup_last_time_ms
163 Date: September 2010 151 Date: September 2010
164 Contact: Rafael J. Wysocki <rjw@rjwysock !! 152 Contact: Rafael J. Wysocki <rjw@sisk.pl>
165 Description: 153 Description:
166 The /sys/devices/.../wakeup_la 154 The /sys/devices/.../wakeup_last_time_ms attribute contains
167 the value of the monotonic clo 155 the value of the monotonic clock corresponding to the time of
168 signaling the last wakeup even 156 signaling the last wakeup event associated with the device, in
169 milliseconds. This attribute 157 milliseconds. This attribute is read-only. If the device is
170 not enabled to wake up the sys 158 not enabled to wake up the system from sleep states, this
171 attribute is not present. If !! 159 attribute is not present.
172 up the system from sleep state <<
173 160
174 What: /sys/devices/.../power/wakeup_ 161 What: /sys/devices/.../power/wakeup_prevent_sleep_time_ms
175 Date: February 2012 162 Date: February 2012
176 Contact: Rafael J. Wysocki <rjw@rjwysock !! 163 Contact: Rafael J. Wysocki <rjw@sisk.pl>
177 Description: 164 Description:
178 The /sys/devices/.../wakeup_pr 165 The /sys/devices/.../wakeup_prevent_sleep_time_ms attribute
179 contains the total time the de 166 contains the total time the device has been preventing
180 opportunistic transitions to s 167 opportunistic transitions to sleep states from occurring.
181 This attribute is read-only. !! 168 This attribute is read-only. If the device is not enabled to
182 wake up the system from sleep 169 wake up the system from sleep states, this attribute is not
183 present. If the device is not !! 170 present.
184 from sleep states, this attrib <<
185 171
186 What: /sys/devices/.../power/autosus 172 What: /sys/devices/.../power/autosuspend_delay_ms
187 Date: September 2010 173 Date: September 2010
188 Contact: Alan Stern <stern@rowland.harva 174 Contact: Alan Stern <stern@rowland.harvard.edu>
189 Description: 175 Description:
190 The /sys/devices/.../power/aut 176 The /sys/devices/.../power/autosuspend_delay_ms attribute
191 contains the autosuspend delay 177 contains the autosuspend delay value (in milliseconds). Some
192 drivers do not want their devi 178 drivers do not want their device to suspend as soon as it
193 becomes idle at run time; they 179 becomes idle at run time; they want the device to remain
194 inactive for a certain minimum 180 inactive for a certain minimum period of time first. That
195 period is called the autosuspe 181 period is called the autosuspend delay. Negative values will
196 prevent the device from being 182 prevent the device from being suspended at run time (similar
197 to writing "on" to the power/c 183 to writing "on" to the power/control attribute). Values >=
198 1000 will cause the autosuspen 184 1000 will cause the autosuspend timer expiration to be rounded
199 up to the nearest second. 185 up to the nearest second.
200 186
201 Not all drivers support this a 187 Not all drivers support this attribute. If it isn't supported,
202 attempts to read or write it w 188 attempts to read or write it will yield I/O errors.
203 189
204 What: /sys/devices/.../power/pm_qos_ !! 190 What: /sys/devices/.../power/pm_qos_latency_us
205 Date: March 2012 191 Date: March 2012
206 Contact: Rafael J. Wysocki <rjw@rjwysock !! 192 Contact: Rafael J. Wysocki <rjw@sisk.pl>
207 Description: 193 Description:
208 The /sys/devices/.../power/pm_ 194 The /sys/devices/.../power/pm_qos_resume_latency_us attribute
209 contains the PM QoS resume lat 195 contains the PM QoS resume latency limit for the given device,
210 which is the maximum allowed t 196 which is the maximum allowed time it can take to resume the
211 device, after it has been susp 197 device, after it has been suspended at run time, from a resume
212 request to the moment the devi 198 request to the moment the device will be ready to process I/O,
213 in microseconds. If it is equ 199 in microseconds. If it is equal to 0, however, this means that
214 the PM QoS resume latency may !! 200 the PM QoS resume latency may be arbitrary.
215 "n/a" means that user space ca <<
216 all for the given device. <<
217 201
218 Not all drivers support this a 202 Not all drivers support this attribute. If it isn't supported,
219 it is not present. 203 it is not present.
220 204
221 This attribute has no effect o 205 This attribute has no effect on system-wide suspend/resume and
222 hibernation. 206 hibernation.
223 207
224 What: /sys/devices/.../power/pm_qos_ <<
225 Date: January 2014 <<
226 Contact: Rafael J. Wysocki <rjw@rjwysock <<
227 Description: <<
228 The /sys/devices/.../power/pm_ <<
229 contains the PM QoS active sta <<
230 given device in microseconds. <<
231 latency the device can suffer <<
232 effects on user space function <<
233 string "any", the latency does <<
234 but hardware should not be all <<
235 for the device automatically. <<
236 <<
237 Reading "auto" from this file <<
238 access latency for the device <<
239 by the hardware as needed. Wr <<
240 hardware to be switched to thi <<
241 latency tolerance requirements <<
242 <<
243 This attribute is only present <<
244 is supported by the hardware. <<
245 <<
246 This attribute has no effect o <<
247 devices and on system-wide sus <<
248 <<
249 What: /sys/devices/.../power/pm_qos_ 208 What: /sys/devices/.../power/pm_qos_no_power_off
250 Date: September 2012 209 Date: September 2012
251 Contact: Rafael J. Wysocki <rjw@rjwysock !! 210 Contact: Rafael J. Wysocki <rjw@sisk.pl>
252 Description: 211 Description:
253 The /sys/devices/.../power/pm_ 212 The /sys/devices/.../power/pm_qos_no_power_off attribute
254 is used for manipulating the P 213 is used for manipulating the PM QoS "no power off" flag. If
255 set, this flag indicates to th 214 set, this flag indicates to the kernel that power should not
256 be removed entirely from the d 215 be removed entirely from the device.
257 216
258 Not all drivers support this a 217 Not all drivers support this attribute. If it isn't supported,
259 it is not present. 218 it is not present.
260 219
261 This attribute has no effect o 220 This attribute has no effect on system-wide suspend/resume and
262 hibernation. 221 hibernation.
263 222
264 What: /sys/devices/.../power/runtime !! 223 What: /sys/devices/.../power/pm_qos_remote_wakeup
265 Date: April 2010 !! 224 Date: September 2012
266 Contact: Rafael J. Wysocki <rjw@rjwysock !! 225 Contact: Rafael J. Wysocki <rjw@sisk.pl>
267 Description: <<
268 The /sys/devices/.../power/run <<
269 the current runtime PM status <<
270 "suspended", "suspending", "re <<
271 error), or "unsupported" (runt <<
272 <<
273 What: /sys/devices/.../power/runtime <<
274 Date: Jul 2010 <<
275 Contact: Arjan van de Ven <arjan@linux.i <<
276 Description: <<
277 Reports the total time that th <<
278 Used for runtime PM statistics <<
279 <<
280 What: /sys/devices/.../power/runtime <<
281 Date: Jul 2010 <<
282 Contact: Arjan van de Ven <arjan@linux.i <<
283 Description: <<
284 Reports total time that the de <<
285 Used for runtime PM statistics <<
286 <<
287 What: /sys/devices/.../power/runtime <<
288 Date: Apr 2010 <<
289 Contact: Dominik Brodowski <linux@domini <<
290 Description: <<
291 Reports the runtime PM usage c <<
292 <<
293 What: /sys/devices/.../power/runtime <<
294 Date: Apr 2010 <<
295 Contact: Dominik Brodowski <linux@domini <<
296 Description: 226 Description:
297 Is runtime PM enabled for this !! 227 The /sys/devices/.../power/pm_qos_remote_wakeup attribute
298 States are "enabled", "disable !! 228 is used for manipulating the PM QoS "remote wakeup required"
299 combination of the latter two. !! 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.
300 232
301 What: /sys/devices/.../power/runtime !! 233 Not all drivers support this attribute. If it isn't supported,
302 Date: Apr 2010 !! 234 it is not present.
303 Contact: Dominik Brodowski <linux@domini <<
304 Description: <<
305 Reports the runtime PM childre <<
306 0 if the children will be igno <<
307 235
>> 236 This attribute has no effect on system-wide suspend/resume and
>> 237 hibernation.
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