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-rw-r--r--Documentation/power/runtime_pm.txt31
1 files changed, 31 insertions, 0 deletions
diff --git a/Documentation/power/runtime_pm.txt b/Documentation/power/runtime_pm.txt
index 41cc7b30d7dd..ffe55ffa540a 100644
--- a/Documentation/power/runtime_pm.txt
+++ b/Documentation/power/runtime_pm.txt
@@ -50,6 +50,15 @@ type's callbacks are not defined) of given device. The bus type, device type
50and device class callbacks are referred to as subsystem-level callbacks in what 50and device class callbacks are referred to as subsystem-level callbacks in what
51follows. 51follows.
52 52
53By default, the callbacks are always invoked in process context with interrupts
54enabled. However, subsystems can use the pm_runtime_irq_safe() helper function
55to tell the PM core that a device's ->runtime_suspend() and ->runtime_resume()
56callbacks should be invoked in atomic context with interrupts disabled
57(->runtime_idle() is still invoked the default way). This implies that these
58callback routines must not block or sleep, but it also means that the
59synchronous helper functions listed at the end of Section 4 can be used within
60an interrupt handler or in an atomic context.
61
53The subsystem-level suspend callback is _entirely_ _responsible_ for handling 62The subsystem-level suspend callback is _entirely_ _responsible_ for handling
54the suspend of the device as appropriate, which may, but need not include 63the suspend of the device as appropriate, which may, but need not include
55executing the device driver's own ->runtime_suspend() callback (from the 64executing the device driver's own ->runtime_suspend() callback (from the
@@ -237,6 +246,10 @@ defined in include/linux/pm.h:
237 Section 8); it may be modified only by the pm_runtime_no_callbacks() 246 Section 8); it may be modified only by the pm_runtime_no_callbacks()
238 helper function 247 helper function
239 248
249 unsigned int irq_safe;
250 - indicates that the ->runtime_suspend() and ->runtime_resume() callbacks
251 will be invoked with the spinlock held and interrupts disabled
252
240 unsigned int use_autosuspend; 253 unsigned int use_autosuspend;
241 - indicates that the device's driver supports delayed autosuspend (see 254 - indicates that the device's driver supports delayed autosuspend (see
242 Section 9); it may be modified only by the 255 Section 9); it may be modified only by the
@@ -344,6 +357,10 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h:
344 - decrement the device's usage counter; if the result is 0 then run 357 - decrement the device's usage counter; if the result is 0 then run
345 pm_runtime_idle(dev) and return its result 358 pm_runtime_idle(dev) and return its result
346 359
360 int pm_runtime_put_sync_suspend(struct device *dev);
361 - decrement the device's usage counter; if the result is 0 then run
362 pm_runtime_suspend(dev) and return its result
363
347 int pm_runtime_put_sync_autosuspend(struct device *dev); 364 int pm_runtime_put_sync_autosuspend(struct device *dev);
348 - decrement the device's usage counter; if the result is 0 then run 365 - decrement the device's usage counter; if the result is 0 then run
349 pm_runtime_autosuspend(dev) and return its result 366 pm_runtime_autosuspend(dev) and return its result
@@ -397,6 +414,11 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h:
397 PM attributes from /sys/devices/.../power (or prevent them from being 414 PM attributes from /sys/devices/.../power (or prevent them from being
398 added when the device is registered) 415 added when the device is registered)
399 416
417 void pm_runtime_irq_safe(struct device *dev);
418 - set the power.irq_safe flag for the device, causing the runtime-PM
419 suspend and resume callbacks (but not the idle callback) to be invoked
420 with interrupts disabled
421
400 void pm_runtime_mark_last_busy(struct device *dev); 422 void pm_runtime_mark_last_busy(struct device *dev);
401 - set the power.last_busy field to the current time 423 - set the power.last_busy field to the current time
402 424
@@ -438,6 +460,15 @@ pm_runtime_suspended()
438pm_runtime_mark_last_busy() 460pm_runtime_mark_last_busy()
439pm_runtime_autosuspend_expiration() 461pm_runtime_autosuspend_expiration()
440 462
463If pm_runtime_irq_safe() has been called for a device then the following helper
464functions may also be used in interrupt context:
465
466pm_runtime_suspend()
467pm_runtime_autosuspend()
468pm_runtime_resume()
469pm_runtime_get_sync()
470pm_runtime_put_sync_suspend()
471
4415. Run-time PM Initialization, Device Probing and Removal 4725. Run-time PM Initialization, Device Probing and Removal
442 473
443Initially, the run-time PM is disabled for all devices, which means that the 474Initially, the run-time PM is disabled for all devices, which means that the