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Commit fa7fd6fa authored by Sudeep Holla's avatar Sudeep Holla Committed by Rafael J. Wysocki
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PM / sleep: enable suspend-to-idle even without registered suspend_ops 



Suspend-to-idle (aka the "freeze" sleep state) is a system sleep state
in which all of the processors enter deepest possible idle state and
wait for interrupts right after suspending all the devices.

There is no hard requirement for a platform to support and register
platform specific suspend_ops to enter suspend-to-idle/freeze state.
Only deeper system sleep states like PM_SUSPEND_STANDBY and
PM_SUSPEND_MEM rely on such low level support/implementation.

suspend-to-idle can be entered as along as all the devices can be
suspended. This patch enables the support for suspend-to-idle even on
systems that don't have any low level support for deeper system sleep
states and/or don't register any platform specific suspend_ops.

Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
Tested-by: default avatarAndy Gross <andy.gross@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 5b3f249c

include/linux/suspend.h

+2 −0
Original line number Diff line number Diff line
@@ -245,6 +245,7 @@ static inline bool idle_should_freeze(void) 
	return unlikely(suspend_freeze_state == FREEZE_STATE_ENTER);

}



extern void __init pm_states_init(void);

extern void freeze_set_ops(const struct platform_freeze_ops *ops);

extern void freeze_wake(void);
@@ -279,6 +280,7 @@ static inline bool pm_resume_via_firmware(void) { return false; } 
static inline void suspend_set_ops(const struct platform_suspend_ops *ops) {}

static inline int pm_suspend(suspend_state_t state) { return -ENOSYS; }

static inline bool idle_should_freeze(void) { return false; }

static inline void __init pm_states_init(void) {}

static inline void freeze_set_ops(const struct platform_freeze_ops *ops) {}

static inline void freeze_wake(void) {}

#endif /* !CONFIG_SUSPEND */

kernel/power/main.c

+1 −0
Original line number Diff line number Diff line
@@ -644,6 +644,7 @@ static int __init pm_init(void) 
		return error;

	hibernate_image_size_init();

	hibernate_reserved_size_init();

	pm_states_init();

	power_kobj = kobject_create_and_add("power", NULL);

	if (!power_kobj)

		return -ENOMEM;

kernel/power/suspend.c

+11 −3
Original line number Diff line number Diff line
@@ -118,10 +118,18 @@ static bool valid_state(suspend_state_t state) 
 */

static bool relative_states;



void __init pm_states_init(void)

{

	/*

	 * freeze state should be supported even without any suspend_ops,

	 * initialize pm_states accordingly here

	 */

	pm_states[PM_SUSPEND_FREEZE] = pm_labels[relative_states ? 0 : 2];

}



static int __init sleep_states_setup(char *str)

{

	relative_states = !strncmp(str, "1", 1);

	pm_states[PM_SUSPEND_FREEZE] = pm_labels[relative_states ? 0 : 2];

	return 1;

}
@@ -211,7 +219,7 @@ static int platform_suspend_begin(suspend_state_t state) 
{

	if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->begin)

		return freeze_ops->begin();

	else if (suspend_ops->begin)

	else if (suspend_ops && suspend_ops->begin)

		return suspend_ops->begin(state);

	else

		return 0;
@@ -221,7 +229,7 @@ static void platform_resume_end(suspend_state_t state) 
{

	if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->end)

		freeze_ops->end();

	else if (suspend_ops->end)

	else if (suspend_ops && suspend_ops->end)

		suspend_ops->end();

}