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PM / sleep: enable suspend-to-idle even without registered suspend_ops

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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: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Andy Gross <andy.gross@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Sudeep Holla 2016-08-19 14:41:00 +01:00 committed by Rafael J. Wysocki
parent 5b3f249c94
commit fa7fd6fa38
3 changed files with 14 additions and 3 deletions
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2
include/linux/suspend.h
View File

@ -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 */

1
kernel/power/main.c
View File

@ -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;

14
kernel/power/suspend.c
View File

@ -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();
}