Commit 9659cc06 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

PM: Make system-wide PM and runtime PM treat subsystems consistently 



The code handling system-wide power transitions (eg. suspend-to-RAM)
can in theory execute callbacks provided by the device's bus type,
device type and class in each phase of the power transition.  In
turn, the runtime PM core code only calls one of those callbacks at
a time, preferring bus type callbacks to device type or class
callbacks and device type callbacks to class callbacks.

It seems reasonable to make them both behave in the same way in that
respect.  Moreover, even though a device may belong to two subsystems
(eg. bus type and device class) simultaneously, in practice power
management callbacks for system-wide power transitions are always
provided by only one of them (ie. if the bus type callbacks are
defined, the device class ones are not and vice versa).  Thus it is
possible to modify the code handling system-wide power transitions
so that it follows the core runtime PM code (ie. treats the
subsystem callbacks as mutually exclusive).

On the other hand, the core runtime PM code will choose to execute,
for example, a runtime suspend callback provided by the device type
even if the bus type's struct dev_pm_ops object exists, but the
runtime_suspend pointer in it happens to be NULL.  This is confusing,
because it may lead to the execution of callbacks from different
subsystems during different operations (eg. the bus type suspend
callback may be executed during runtime suspend of the device, while
the device type callback will be executed during system suspend).

Make all of the power management code treat subsystem callbacks in
a consistent way, such that:
(1) If the device's type is defined (eg. dev->type is not NULL)
    and its pm pointer is not NULL, the callbacks from dev->type->pm
    will be used.
(2) If dev->type is NULL or dev->type->pm is NULL, but the device's
    class is defined (eg. dev->class is not NULL) and its pm pointer
    is not NULL, the callbacks from dev->class->pm will be used.
(3) If dev->type is NULL or dev->type->pm is NULL and dev->class is
    NULL or dev->class->pm is NULL, the callbacks from dev->bus->pm
    will be used provided that both dev->bus and dev->bus->pm are
    not NULL.

Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Acked-by: default avatarKevin Hilman <khilman@ti.com>
Reasoning-sounds-sane-to: Grant Likely <grant.likely@secretlab.ca>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent cf4fb80c

Documentation/power/devices.txt

+12 −17
Original line number Diff line number Diff line
@@ -249,23 +249,18 @@ various phases always run after tasks have been frozen and before they are 
unfrozen.  Furthermore, the *_noirq phases run at a time when IRQ handlers have

been disabled (except for those marked with the IRQ_WAKEUP flag).



Most phases use bus, type, and class callbacks (that is, methods defined in

dev->bus->pm, dev->type->pm, and dev->class->pm).  The prepare and complete

phases are exceptions; they use only bus callbacks.  When multiple callbacks

are used in a phase, they are invoked in the order: <class, type, bus> during

power-down transitions and in the opposite order during power-up transitions.

For example, during the suspend phase the PM core invokes



	dev->class->pm.suspend(dev);

	dev->type->pm.suspend(dev);

	dev->bus->pm.suspend(dev);



before moving on to the next device, whereas during the resume phase the core

invokes



	dev->bus->pm.resume(dev);

	dev->type->pm.resume(dev);

	dev->class->pm.resume(dev);

All phases use bus, type, or class callbacks (that is, methods defined in

dev->bus->pm, dev->type->pm, or dev->class->pm).  These callbacks are mutually

exclusive, so if the device type provides a struct dev_pm_ops object pointed to

by its pm field (i.e. both dev->type and dev->type->pm are defined), the

callbacks included in that object (i.e. dev->type->pm) will be used.  Otherwise,

if the class provides a struct dev_pm_ops object pointed to by its pm field

(i.e. both dev->class and dev->class->pm are defined), the PM core will use the

callbacks from that object (i.e. dev->class->pm).  Finally, if the pm fields of

both the device type and class objects are NULL (or those objects do not exist),

the callbacks provided by the bus (that is, the callbacks from dev->bus->pm)

will be used (this allows device types to override callbacks provided by bus

types or classes if necessary).



These callbacks may in turn invoke device- or driver-specific methods stored in

dev->driver->pm, but they don't have to.

Documentation/power/runtime_pm.txt

+7 −6
Original line number Diff line number Diff line 
Run-time Power Management Framework for I/O Devices



(C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.

(C) 2009-2011 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.

(C) 2010 Alan Stern <stern@rowland.harvard.edu>



1. Introduction
@@ -44,11 +44,12 @@ struct dev_pm_ops { 
};



The ->runtime_suspend(), ->runtime_resume() and ->runtime_idle() callbacks are

executed by the PM core for either the bus type, or device type (if the bus

type's callback is not defined), or device class (if the bus type's and device

type's callbacks are not defined) of given device.  The bus type, device type

and device class callbacks are referred to as subsystem-level callbacks in what

follows.

executed by the PM core for either the device type, or the class (if the device

type's struct dev_pm_ops object does not exist), or the bus type (if the

device type's and class' struct dev_pm_ops objects do not exist) of the given

device (this allows device types to override callbacks provided by bus types or

classes if necessary).  The bus type, device type and class callbacks are

referred to as subsystem-level callbacks in what follows.



By default, the callbacks are always invoked in process context with interrupts

enabled.  However, subsystems can use the pm_runtime_irq_safe() helper function

drivers/base/power/main.c

+64 −86
Original line number Diff line number Diff line
@@ -428,26 +428,17 @@ static int device_resume_noirq(struct device *dev, pm_message_t state) 
		pm_noirq_op(dev, &dev->pwr_domain->ops, state);

	}



	if (dev->bus && dev->bus->pm) {

		pm_dev_dbg(dev, state, "EARLY ");

		error = pm_noirq_op(dev, dev->bus->pm, state);

		if (error)

			goto End;

	}



	if (dev->type && dev->type->pm) {

		pm_dev_dbg(dev, state, "EARLY type ");

		error = pm_noirq_op(dev, dev->type->pm, state);

		if (error)

			goto End;

	}



	if (dev->class && dev->class->pm) {

	} else if (dev->class && dev->class->pm) {

		pm_dev_dbg(dev, state, "EARLY class ");

		error = pm_noirq_op(dev, dev->class->pm, state);

	} else if (dev->bus && dev->bus->pm) {

		pm_dev_dbg(dev, state, "EARLY ");

		error = pm_noirq_op(dev, dev->bus->pm, state);

	}



End:

	TRACE_RESUME(error);

	return error;

}
@@ -528,24 +519,9 @@ static int device_resume(struct device *dev, pm_message_t state, bool async) 
		pm_op(dev, &dev->pwr_domain->ops, state);

	}



	if (dev->bus) {

		if (dev->bus->pm) {

			pm_dev_dbg(dev, state, "");

			error = pm_op(dev, dev->bus->pm, state);

		} else if (dev->bus->resume) {

			pm_dev_dbg(dev, state, "legacy ");

			error = legacy_resume(dev, dev->bus->resume);

		}

		if (error)

			goto End;

	}



	if (dev->type) {

		if (dev->type->pm) {

	if (dev->type && dev->type->pm) {

		pm_dev_dbg(dev, state, "type ");

		error = pm_op(dev, dev->type->pm, state);

		}

		if (error)

		goto End;

	}
@@ -553,11 +529,24 @@ static int device_resume(struct device *dev, pm_message_t state, bool async) 
		if (dev->class->pm) {

			pm_dev_dbg(dev, state, "class ");

			error = pm_op(dev, dev->class->pm, state);

			goto End;

		} else if (dev->class->resume) {

			pm_dev_dbg(dev, state, "legacy class ");

			error = legacy_resume(dev, dev->class->resume);

			goto End;

		}

	}



	if (dev->bus) {

		if (dev->bus->pm) {

			pm_dev_dbg(dev, state, "");

			error = pm_op(dev, dev->bus->pm, state);

		} else if (dev->bus->resume) {

			pm_dev_dbg(dev, state, "legacy ");

			error = legacy_resume(dev, dev->bus->resume);

		}

	}



 End:

	device_unlock(dev);

	complete_all(&dev->power.completion);
@@ -644,18 +633,17 @@ static void device_complete(struct device *dev, pm_message_t state) 
		dev->pwr_domain->ops.complete(dev);

	}



	if (dev->class && dev->class->pm && dev->class->pm->complete) {

		pm_dev_dbg(dev, state, "completing class ");

		dev->class->pm->complete(dev);

	}



	if (dev->type && dev->type->pm && dev->type->pm->complete) {

	if (dev->type && dev->type->pm) {

		pm_dev_dbg(dev, state, "completing type ");

		if (dev->type->pm->complete)

			dev->type->pm->complete(dev);

	}



	if (dev->bus && dev->bus->pm && dev->bus->pm->complete) {

	} else if (dev->class && dev->class->pm) {

		pm_dev_dbg(dev, state, "completing class ");

		if (dev->class->pm->complete)

			dev->class->pm->complete(dev);

	} else if (dev->bus && dev->bus->pm) {

		pm_dev_dbg(dev, state, "completing ");

		if (dev->bus->pm->complete)

			dev->bus->pm->complete(dev);

	}
@@ -741,27 +729,23 @@ static pm_message_t resume_event(pm_message_t sleep_state) 
 */

static int device_suspend_noirq(struct device *dev, pm_message_t state)

{

	int error = 0;



	if (dev->class && dev->class->pm) {

		pm_dev_dbg(dev, state, "LATE class ");

		error = pm_noirq_op(dev, dev->class->pm, state);

		if (error)

			goto End;

	}

	int error;



	if (dev->type && dev->type->pm) {

		pm_dev_dbg(dev, state, "LATE type ");

		error = pm_noirq_op(dev, dev->type->pm, state);

		if (error)

			goto End;

	}



	if (dev->bus && dev->bus->pm) {

			return error;

	} else if (dev->class && dev->class->pm) {

		pm_dev_dbg(dev, state, "LATE class ");

		error = pm_noirq_op(dev, dev->class->pm, state);

		if (error)

			return error;

	} else if (dev->bus && dev->bus->pm) {

		pm_dev_dbg(dev, state, "LATE ");

		error = pm_noirq_op(dev, dev->bus->pm, state);

		if (error)

			goto End;

			return error;

	}



	if (dev->pwr_domain) {
@@ -769,8 +753,7 @@ static int device_suspend_noirq(struct device *dev, pm_message_t state) 
		pm_noirq_op(dev, &dev->pwr_domain->ops, state);

	}



End:

	return error;

	return 0;

}



/**
@@ -857,25 +840,22 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async) 
		goto End;

	}



	if (dev->type && dev->type->pm) {

		pm_dev_dbg(dev, state, "type ");

		error = pm_op(dev, dev->type->pm, state);

		goto Domain;

	}



	if (dev->class) {

		if (dev->class->pm) {

			pm_dev_dbg(dev, state, "class ");

			error = pm_op(dev, dev->class->pm, state);

			goto Domain;

		} else if (dev->class->suspend) {

			pm_dev_dbg(dev, state, "legacy class ");

			error = legacy_suspend(dev, state, dev->class->suspend);

			goto Domain;

		}

		if (error)

			goto End;

	}



	if (dev->type) {

		if (dev->type->pm) {

			pm_dev_dbg(dev, state, "type ");

			error = pm_op(dev, dev->type->pm, state);

		}

		if (error)

			goto End;

	}



	if (dev->bus) {
@@ -886,11 +866,10 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async) 
			pm_dev_dbg(dev, state, "legacy ");

			error = legacy_suspend(dev, state, dev->bus->suspend);

		}

		if (error)

			goto End;

	}



	if (dev->pwr_domain) {

 Domain:

	if (!error && dev->pwr_domain) {

		pm_dev_dbg(dev, state, "power domain ");

		pm_op(dev, &dev->pwr_domain->ops, state);

	}
@@ -985,28 +964,27 @@ static int device_prepare(struct device *dev, pm_message_t state) 


	device_lock(dev);



	if (dev->bus && dev->bus->pm && dev->bus->pm->prepare) {

		pm_dev_dbg(dev, state, "preparing ");

		error = dev->bus->pm->prepare(dev);

		suspend_report_result(dev->bus->pm->prepare, error);

		if (error)

			goto End;

	}



	if (dev->type && dev->type->pm && dev->type->pm->prepare) {

	if (dev->type && dev->type->pm) {

		pm_dev_dbg(dev, state, "preparing type ");

		if (dev->type->pm->prepare)

			error = dev->type->pm->prepare(dev);

		suspend_report_result(dev->type->pm->prepare, error);

		if (error)

			goto End;

	}



	if (dev->class && dev->class->pm && dev->class->pm->prepare) {

	} else if (dev->class && dev->class->pm) {

		pm_dev_dbg(dev, state, "preparing class ");

		if (dev->class->pm->prepare)

			error = dev->class->pm->prepare(dev);

		suspend_report_result(dev->class->pm->prepare, error);

		if (error)

			goto End;

	} else if (dev->bus && dev->bus->pm) {

		pm_dev_dbg(dev, state, "preparing ");

		if (dev->bus->pm->prepare)

			error = dev->bus->pm->prepare(dev);

		suspend_report_result(dev->bus->pm->prepare, error);

		if (error)

			goto End;

	}



	if (dev->pwr_domain && dev->pwr_domain->ops.prepare) {

drivers/base/power/runtime.c

+9 −9
Original line number Diff line number Diff line
@@ -214,12 +214,12 @@ static int rpm_idle(struct device *dev, int rpmflags) 


	dev->power.idle_notification = true;



	if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_idle)

		callback = dev->bus->pm->runtime_idle;

	else if (dev->type && dev->type->pm && dev->type->pm->runtime_idle)

	if (dev->type && dev->type->pm)

		callback = dev->type->pm->runtime_idle;

	else if (dev->class && dev->class->pm)

		callback = dev->class->pm->runtime_idle;

	else if (dev->bus && dev->bus->pm)

		callback = dev->bus->pm->runtime_idle;

	else

		callback = NULL;
@@ -382,12 +382,12 @@ static int rpm_suspend(struct device *dev, int rpmflags) 


	__update_runtime_status(dev, RPM_SUSPENDING);



	if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_suspend)

		callback = dev->bus->pm->runtime_suspend;

	else if (dev->type && dev->type->pm && dev->type->pm->runtime_suspend)

	if (dev->type && dev->type->pm)

		callback = dev->type->pm->runtime_suspend;

	else if (dev->class && dev->class->pm)

		callback = dev->class->pm->runtime_suspend;

	else if (dev->bus && dev->bus->pm)

		callback = dev->bus->pm->runtime_suspend;

	else

		callback = NULL;
@@ -584,12 +584,12 @@ static int rpm_resume(struct device *dev, int rpmflags) 
	if (dev->pwr_domain)

		rpm_callback(dev->pwr_domain->ops.runtime_resume, dev);



	if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_resume)

		callback = dev->bus->pm->runtime_resume;

	else if (dev->type && dev->type->pm && dev->type->pm->runtime_resume)

	if (dev->type && dev->type->pm)

		callback = dev->type->pm->runtime_resume;

	else if (dev->class && dev->class->pm)

		callback = dev->class->pm->runtime_resume;

	else if (dev->bus && dev->bus->pm)

		callback = dev->bus->pm->runtime_resume;

	else

		callback = NULL;

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