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. Cc: "Rafael J. Wysocki" <[email protected]> Signed-off-by: Sudeep Holla <[email protected]> --- include/linux/suspend.h | 2 ++ kernel/power/main.c | 1 + kernel/power/suspend.c | 14 +++++++++++--- 3 files changed, 14 insertions(+), 3 deletions(-) v1->v2: - Introduced pm_freeze_init instead of (mis/re)using suspend_set_ops to setup freeze state in absense of registered platform suspend_ops diff --git a/include/linux/suspend.h b/include/linux/suspend.h index 7693e39b14fe..0528ee32be7c 100644 --- a/include/linux/suspend.h +++ b/include/linux/suspend.h @@ -245,6 +245,7 @@ static inline bool idle_should_freeze(void) return unlikely(suspend_freeze_state == FREEZE_STATE_ENTER); } +extern void __init pm_freeze_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_freeze_init(void) {} static inline void freeze_set_ops(const struct platform_freeze_ops *ops) {} static inline void freeze_wake(void) {} #endif /* !CONFIG_SUSPEND */ diff --git a/kernel/power/main.c b/kernel/power/main.c index 5ea50b1b7595..f27c2f2d0f22 100644 --- a/kernel/power/main.c +++ b/kernel/power/main.c @@ -651,6 +651,7 @@ static int __init pm_init(void) if (error) return error; pm_print_times_init(); + pm_freeze_init(); return pm_autosleep_init(); } diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 0acab9d7f96f..1c962a366678 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -118,10 +118,18 @@ static bool valid_state(suspend_state_t state) */ static bool relative_states; +void __init pm_freeze_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(); } -- 2.7.4
