diff options
author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2014-02-10 18:35:23 -0500 |
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committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2014-02-10 18:35:23 -0500 |
commit | b02f6695f7601c4f8442b9cf4636802e7fa8d550 (patch) | |
tree | 6a4735abce3fc9a27e029f15a051d07fda92f190 /Documentation/power | |
parent | b28a960c42fcd9cfc987441fa6d1c1a471f0f9ed (diff) |
PM / QoS: Rename device resume latency QoS items
Rename symbols, variables, functions and structure fields related do
the resume latency device PM QoS type so that it is clear where they
belong (in particular, to avoid confusion with the latency tolerance
device PM QoS type introduced by a subsequent changeset).
Update the PM QoS documentation to better reflect its current state.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation/power')
-rw-r--r-- | Documentation/power/pm_qos_interface.txt | 37 |
1 files changed, 16 insertions, 21 deletions
diff --git a/Documentation/power/pm_qos_interface.txt b/Documentation/power/pm_qos_interface.txt index 483632087788..22cb8f51182a 100644 --- a/Documentation/power/pm_qos_interface.txt +++ b/Documentation/power/pm_qos_interface.txt | |||
@@ -89,16 +89,16 @@ node. | |||
89 | 2. PM QoS per-device latency and flags framework | 89 | 2. PM QoS per-device latency and flags framework |
90 | 90 | ||
91 | For each device, there are two lists of PM QoS requests. One is maintained | 91 | For each device, there are two lists of PM QoS requests. One is maintained |
92 | along with the aggregated target of latency value and the other is for PM QoS | 92 | along with the aggregated target of resume latency value and the other is for |
93 | flags. Values are updated in response to changes of the request list. | 93 | PM QoS flags. Values are updated in response to changes of the request list. |
94 | 94 | ||
95 | Target latency value is simply the minimum of the request values held in the | 95 | Target resume latency value is simply the minimum of the request values held in |
96 | parameter list elements. The PM QoS flags aggregate value is a gather (bitwise | 96 | the parameter list elements. The PM QoS flags aggregate value is a gather |
97 | OR) of all list elements' values. Two device PM QoS flags are defined currently: | 97 | (bitwise OR) of all list elements' values. Two device PM QoS flags are defined |
98 | PM_QOS_FLAG_NO_POWER_OFF and PM_QOS_FLAG_REMOTE_WAKEUP. | 98 | currently: PM_QOS_FLAG_NO_POWER_OFF and PM_QOS_FLAG_REMOTE_WAKEUP. |
99 | 99 | ||
100 | Note: the aggregated target value is implemented as an atomic variable so that | 100 | Note: the aggregated target value is implemented in such a way that reading the |
101 | reading the aggregated value does not require any locking mechanism. | 101 | aggregated value does not require any locking mechanism. |
102 | 102 | ||
103 | 103 | ||
104 | From kernel mode the use of this interface is the following: | 104 | From kernel mode the use of this interface is the following: |
@@ -137,14 +137,14 @@ Add a PM QoS request for the first direct ancestor of the given device whose | |||
137 | power.ignore_children flag is unset. | 137 | power.ignore_children flag is unset. |
138 | 138 | ||
139 | int dev_pm_qos_expose_latency_limit(device, value) | 139 | int dev_pm_qos_expose_latency_limit(device, value) |
140 | Add a request to the device's PM QoS list of latency constraints and create | 140 | Add a request to the device's PM QoS list of resume latency constraints and |
141 | a sysfs attribute pm_qos_resume_latency_us under the device's power directory | 141 | create a sysfs attribute pm_qos_resume_latency_us under the device's power |
142 | allowing user space to manipulate that request. | 142 | directory allowing user space to manipulate that request. |
143 | 143 | ||
144 | void dev_pm_qos_hide_latency_limit(device) | 144 | void dev_pm_qos_hide_latency_limit(device) |
145 | Drop the request added by dev_pm_qos_expose_latency_limit() from the device's | 145 | Drop the request added by dev_pm_qos_expose_latency_limit() from the device's |
146 | PM QoS list of latency constraints and remove sysfs attribute pm_qos_resume_latency_us | 146 | PM QoS list of resume latency constraints and remove sysfs attribute |
147 | from the device's power directory. | 147 | pm_qos_resume_latency_us from the device's power directory. |
148 | 148 | ||
149 | int dev_pm_qos_expose_flags(device, value) | 149 | int dev_pm_qos_expose_flags(device, value) |
150 | Add a request to the device's PM QoS list of flags and create sysfs attributes | 150 | Add a request to the device's PM QoS list of flags and create sysfs attributes |
@@ -163,7 +163,7 @@ a per-device notification tree and a global notification tree. | |||
163 | int dev_pm_qos_add_notifier(device, notifier): | 163 | int dev_pm_qos_add_notifier(device, notifier): |
164 | Adds a notification callback function for the device. | 164 | Adds a notification callback function for the device. |
165 | The callback is called when the aggregated value of the device constraints list | 165 | The callback is called when the aggregated value of the device constraints list |
166 | is changed. | 166 | is changed (for resume latency device PM QoS only). |
167 | 167 | ||
168 | int dev_pm_qos_remove_notifier(device, notifier): | 168 | int dev_pm_qos_remove_notifier(device, notifier): |
169 | Removes the notification callback function for the device. | 169 | Removes the notification callback function for the device. |
@@ -171,14 +171,9 @@ Removes the notification callback function for the device. | |||
171 | int dev_pm_qos_add_global_notifier(notifier): | 171 | int dev_pm_qos_add_global_notifier(notifier): |
172 | Adds a notification callback function in the global notification tree of the | 172 | Adds a notification callback function in the global notification tree of the |
173 | framework. | 173 | framework. |
174 | The callback is called when the aggregated value for any device is changed. | 174 | The callback is called when the aggregated value for any device is changed |
175 | (for resume latency device PM QoS only). | ||
175 | 176 | ||
176 | int dev_pm_qos_remove_global_notifier(notifier): | 177 | int dev_pm_qos_remove_global_notifier(notifier): |
177 | Removes the notification callback function from the global notification tree | 178 | Removes the notification callback function from the global notification tree |
178 | of the framework. | 179 | of the framework. |
179 | |||
180 | |||
181 | From user mode: | ||
182 | No API for user space access to the per-device latency constraints is provided | ||
183 | yet - still under discussion. | ||
184 | |||