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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-02-10 18:35:23 -0500
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-02-10 18:35:23 -0500
commitb02f6695f7601c4f8442b9cf4636802e7fa8d550 (patch)
tree6a4735abce3fc9a27e029f15a051d07fda92f190 /Documentation/power
parentb28a960c42fcd9cfc987441fa6d1c1a471f0f9ed (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.txt37
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.
892. PM QoS per-device latency and flags framework 892. PM QoS per-device latency and flags framework
90 90
91For each device, there are two lists of PM QoS requests. One is maintained 91For each device, there are two lists of PM QoS requests. One is maintained
92along with the aggregated target of latency value and the other is for PM QoS 92along with the aggregated target of resume latency value and the other is for
93flags. Values are updated in response to changes of the request list. 93PM QoS flags. Values are updated in response to changes of the request list.
94 94
95Target latency value is simply the minimum of the request values held in the 95Target resume latency value is simply the minimum of the request values held in
96parameter list elements. The PM QoS flags aggregate value is a gather (bitwise 96the parameter list elements. The PM QoS flags aggregate value is a gather
97OR) 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
98PM_QOS_FLAG_NO_POWER_OFF and PM_QOS_FLAG_REMOTE_WAKEUP. 98currently: PM_QOS_FLAG_NO_POWER_OFF and PM_QOS_FLAG_REMOTE_WAKEUP.
99 99
100Note: the aggregated target value is implemented as an atomic variable so that 100Note: the aggregated target value is implemented in such a way that reading the
101reading the aggregated value does not require any locking mechanism. 101aggregated value does not require any locking mechanism.
102 102
103 103
104From kernel mode the use of this interface is the following: 104From 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
137power.ignore_children flag is unset. 137power.ignore_children flag is unset.
138 138
139int dev_pm_qos_expose_latency_limit(device, value) 139int dev_pm_qos_expose_latency_limit(device, value)
140Add a request to the device's PM QoS list of latency constraints and create 140Add a request to the device's PM QoS list of resume latency constraints and
141a sysfs attribute pm_qos_resume_latency_us under the device's power directory 141create a sysfs attribute pm_qos_resume_latency_us under the device's power
142allowing user space to manipulate that request. 142directory allowing user space to manipulate that request.
143 143
144void dev_pm_qos_hide_latency_limit(device) 144void dev_pm_qos_hide_latency_limit(device)
145Drop the request added by dev_pm_qos_expose_latency_limit() from the device's 145Drop the request added by dev_pm_qos_expose_latency_limit() from the device's
146PM QoS list of latency constraints and remove sysfs attribute pm_qos_resume_latency_us 146PM QoS list of resume latency constraints and remove sysfs attribute
147from the device's power directory. 147pm_qos_resume_latency_us from the device's power directory.
148 148
149int dev_pm_qos_expose_flags(device, value) 149int dev_pm_qos_expose_flags(device, value)
150Add a request to the device's PM QoS list of flags and create sysfs attributes 150Add 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.
163int dev_pm_qos_add_notifier(device, notifier): 163int dev_pm_qos_add_notifier(device, notifier):
164Adds a notification callback function for the device. 164Adds a notification callback function for the device.
165The callback is called when the aggregated value of the device constraints list 165The callback is called when the aggregated value of the device constraints list
166is changed. 166is changed (for resume latency device PM QoS only).
167 167
168int dev_pm_qos_remove_notifier(device, notifier): 168int dev_pm_qos_remove_notifier(device, notifier):
169Removes the notification callback function for the device. 169Removes the notification callback function for the device.
@@ -171,14 +171,9 @@ Removes the notification callback function for the device.
171int dev_pm_qos_add_global_notifier(notifier): 171int dev_pm_qos_add_global_notifier(notifier):
172Adds a notification callback function in the global notification tree of the 172Adds a notification callback function in the global notification tree of the
173framework. 173framework.
174The callback is called when the aggregated value for any device is changed. 174The callback is called when the aggregated value for any device is changed
175(for resume latency device PM QoS only).
175 176
176int dev_pm_qos_remove_global_notifier(notifier): 177int dev_pm_qos_remove_global_notifier(notifier):
177Removes the notification callback function from the global notification tree 178Removes the notification callback function from the global notification tree
178of the framework. 179of the framework.
179
180
181From user mode:
182No API for user space access to the per-device latency constraints is provided
183yet - still under discussion.
184