From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Currently, some subsystems (e.g. PCI and the ACPI PM domain) have to resume all runtime-suspended devices during system suspend, mostly because those devices may need to be reprogrammed due to different wakeup settings for system sleep and for runtime PM. For some devices, though, it's OK to remain in runtime suspend throughout a complete system suspend/resume cycle (if the device was in runtime suspend at the start of the cycle). We would like to do this whenever possible, to avoid the overhead of extra power-up and power-down events. However, problems may arise because the device's descendants may require it to be at full power at various points during the cycle. Therefore the most straightforward way to do this safely is if the device and all its descendants can remain runtime suspended until the resume stage of system resume. To this end, introduce dev->power.leave_runtime_suspended. If a subsystem or driver sets this flag during the ->prepare() callback, and if the flag is set in all of the device's descendants, and if the device is still in runtime suspend at the beginning of the ->suspend() callback, that callback is allowed to return 0 without clearing power.leave_runtime_suspended and without changing the state of the device, unless the current state of the device is not appropriate for the upcoming system sleep state (for example, the device is supposed to wake up the system from that state and its current wakeup settings are not suitable for that). Then, the PM core will not invoke the device's ->suspend_late(), ->suspend_irq(), ->resume_irq(), ->resume_early(), or ->resume() callbacks. Instead, it will invoke ->runtime_resume() during the device resume stage of system resume. By leaving this flag set after ->suspend(), a driver or subsystem tells the PM core that the device is runtime suspended, it is in a suitable state for system suspend (for example, the wakeup setting does not need to be changed), and it does not need to return to full power until the resume stage. Changelog based on an Alan Stern's description of the idea (http://marc.info/?l=linux-pm&m=139940466625569&w=2). Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> --- drivers/base/power/main.c | 31 ++++++++++++++++++++++++------- drivers/base/power/runtime.c | 10 ++++++++++ include/linux/pm.h | 3 +++ include/linux/pm_runtime.h | 16 ++++++++++++++++ kernel/power/Kconfig | 4 ++++ 5 files changed, 57 insertions(+), 7 deletions(-) Index: linux-pm/kernel/power/Kconfig =================================================================== --- linux-pm.orig/kernel/power/Kconfig +++ linux-pm/kernel/power/Kconfig @@ -147,6 +147,10 @@ config PM def_bool y depends on PM_SLEEP || PM_RUNTIME +config PM_BOTH + def_bool y + depends on PM_SLEEP && PM_RUNTIME + config PM_DEBUG bool "Power Management Debug Support" depends on PM Index: linux-pm/include/linux/pm.h =================================================================== --- linux-pm.orig/include/linux/pm.h +++ linux-pm/include/linux/pm.h @@ -583,6 +583,9 @@ struct dev_pm_info { unsigned long suspended_jiffies; unsigned long accounting_timestamp; #endif +#ifdef CONFIG_PM_BOTH + bool leave_runtime_suspended:1; +#endif struct pm_subsys_data *subsys_data; /* Owned by the subsystem. */ void (*set_latency_tolerance)(struct device *, s32); struct dev_pm_qos *qos; Index: linux-pm/include/linux/pm_runtime.h =================================================================== --- linux-pm.orig/include/linux/pm_runtime.h +++ linux-pm/include/linux/pm_runtime.h @@ -264,4 +264,20 @@ static inline void pm_runtime_dont_use_a __pm_runtime_use_autosuspend(dev, false); } +#ifdef CONFIG_PM_BOTH +static inline void __set_leave_runtime_suspended(struct device *dev, bool val) +{ + dev->power.leave_runtime_suspended = val; +} +extern void pm_set_leave_runtime_suspended(struct device *dev, bool val); +static inline bool pm_leave_runtime_suspended(struct device *dev) +{ + return dev->power.leave_runtime_suspended; +} +#else +static inline void __set_leave_runtime_suspended(struct device *dev, bool val) {} +static inline void pm_set_leave_runtime_suspended(struct device *dev, bool val) {} +static inline bool pm_leave_runtime_suspended(struct device *dev) { return false; } +#endif + #endif Index: linux-pm/drivers/base/power/runtime.c =================================================================== --- linux-pm.orig/drivers/base/power/runtime.c +++ linux-pm/drivers/base/power/runtime.c @@ -732,6 +732,7 @@ static int rpm_resume(struct device *dev } skip_parent: + __set_leave_runtime_suspended(dev, false); if (dev->power.no_callbacks) goto no_callback; /* Assume success. */ @@ -1485,3 +1486,12 @@ out: return ret; } EXPORT_SYMBOL_GPL(pm_runtime_force_resume); + +#ifdef CONFIG_PM_BOTH +void pm_set_leave_runtime_suspended(struct device *dev, bool val) +{ + spin_lock_irq(&dev->power.lock); + __set_leave_runtime_suspended(dev, val); + spin_unlock_irq(&dev->power.lock); +} +#endif Index: linux-pm/drivers/base/power/main.c =================================================================== --- linux-pm.orig/drivers/base/power/main.c +++ linux-pm/drivers/base/power/main.c @@ -479,7 +479,7 @@ static int device_resume_noirq(struct de TRACE_DEVICE(dev); TRACE_RESUME(0); - if (dev->power.syscore) + if (dev->power.syscore || pm_leave_runtime_suspended(dev)) goto Out; if (!dev->power.is_noirq_suspended) @@ -605,7 +605,7 @@ static int device_resume_early(struct de TRACE_DEVICE(dev); TRACE_RESUME(0); - if (dev->power.syscore) + if (dev->power.syscore || pm_leave_runtime_suspended(dev)) goto Out; if (!dev->power.is_late_suspended) @@ -735,6 +735,11 @@ static int device_resume(struct device * if (dev->power.syscore) goto Complete; + if (pm_leave_runtime_suspended(dev)) { + pm_runtime_resume(dev); + goto Complete; + } + dpm_wait(dev->parent, async); dpm_watchdog_set(&wd, dev); device_lock(dev); @@ -1007,7 +1012,7 @@ static int __device_suspend_noirq(struct goto Complete; } - if (dev->power.syscore) + if (dev->power.syscore || pm_leave_runtime_suspended(dev)) goto Complete; dpm_wait_for_children(dev, async); @@ -1146,7 +1151,7 @@ static int __device_suspend_late(struct goto Complete; } - if (dev->power.syscore) + if (dev->power.syscore || pm_leave_runtime_suspended(dev)) goto Complete; dpm_wait_for_children(dev, async); @@ -1382,10 +1387,21 @@ static int __device_suspend(struct devic End: if (!error) { + struct device *parent = dev->parent; + dev->power.is_suspended = true; - if (dev->power.wakeup_path - && dev->parent && !dev->parent->power.ignore_children) - dev->parent->power.wakeup_path = true; + if (parent) { + spin_lock_irq(&parent->power.lock); + + if (dev->power.wakeup_path + && !parent->power.ignore_children) + parent->power.wakeup_path = true; + + if (!pm_leave_runtime_suspended(dev)) + __set_leave_runtime_suspended(parent, false); + + spin_unlock_irq(&parent->power.lock); + } } device_unlock(dev); @@ -1553,6 +1569,7 @@ int dpm_prepare(pm_message_t state) struct device *dev = to_device(dpm_list.next); get_device(dev); + pm_set_leave_runtime_suspended(dev, false); mutex_unlock(&dpm_list_mtx); error = device_prepare(dev, state); -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
