diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 86d5e4fb5b98314d10504f0c91ea5c2765038ddd..343ffad593779d08095132e4207fcc2a7fbfcbbf 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -479,7 +479,7 @@ static int device_resume_noirq(struct device *dev, pm_message_t state, bool asyn
TRACE_DEVICE(dev);
TRACE_RESUME(0);
- if (dev->power.syscore)
+ if (dev->power.syscore || dev->power.direct_complete)
goto Out;
if (!dev->power.is_noirq_suspended)
@@ -605,7 +605,7 @@ static int device_resume_early(struct device *dev, pm_message_t state, bool asyn
TRACE_DEVICE(dev);
TRACE_RESUME(0);
- if (dev->power.syscore)
+ if (dev->power.syscore || dev->power.direct_complete)
goto Out;
if (!dev->power.is_late_suspended)
@@ -735,6 +735,12 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
if (dev->power.syscore)
goto Complete;
+ if (dev->power.direct_complete) {
+ /* Match the pm_runtime_disable() in __device_suspend(). */
+ pm_runtime_enable(dev);
+ goto Complete;
+ }
+
dpm_wait(dev->parent, async);
dpm_watchdog_set(&wd, dev);
device_lock(dev);
@@ -1007,7 +1013,7 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
goto Complete;
}
- if (dev->power.syscore)
+ if (dev->power.syscore || dev->power.direct_complete)
goto Complete;
dpm_wait_for_children(dev, async);
@@ -1146,7 +1152,7 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as
goto Complete;
}
- if (dev->power.syscore)
+ if (dev->power.syscore || dev->power.direct_complete)
goto Complete;
dpm_wait_for_children(dev, async);
@@ -1332,6 +1338,17 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
if (dev->power.syscore)
goto Complete;
+ if (dev->power.direct_complete) {
+ if (pm_runtime_status_suspended(dev)) {
+ pm_runtime_disable(dev);
+ if (pm_runtime_suspended_if_enabled(dev))
+ goto Complete;
+
+ pm_runtime_enable(dev);
+ }
+ dev->power.direct_complete = false;
+ }
+
dpm_watchdog_set(&wd, dev);
device_lock(dev);
@@ -1382,10 +1399,19 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
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);
+
+ dev->parent->power.direct_complete = false;
+ if (dev->power.wakeup_path
+ && !dev->parent->power.ignore_children)
+ dev->parent->power.wakeup_path = true;
+
+ spin_unlock_irq(&parent->power.lock);
+ }
}
device_unlock(dev);
@@ -1487,7 +1513,7 @@ static int device_prepare(struct device *dev, pm_message_t state)
{
int (*callback)(struct device *) = NULL;
char *info = NULL;
- int error = 0;
+ int ret = 0;
if (dev->power.syscore)
return 0;
@@ -1523,17 +1549,27 @@ static int device_prepare(struct device *dev, pm_message_t state)
callback = dev->driver->pm->prepare;
}
- if (callback) {
- error = callback(dev);
- suspend_report_result(callback, error);
- }
+ if (callback)
+ ret = callback(dev);
device_unlock(dev);
- if (error)
+ if (ret < 0) {
+ suspend_report_result(callback, ret);
pm_runtime_put(dev);
-
- return error;
+ return ret;
+ }
+ /*
+ * A positive return value from ->prepare() means "this device appears
+ * to be runtime-suspended and its state is fine, so if it really is
+ * runtime-suspended, you can leave it in that state provided that you
+ * will do the same thing with all of its descendants". This only
+ * applies to suspend transitions, however.
+ */
+ spin_lock_irq(&dev->power.lock);
+ dev->power.direct_complete = ret > 0 && state.event == PM_EVENT_SUSPEND;
+ spin_unlock_irq(&dev->power.lock);
+ return 0;
}
/**
diff --git a/include/linux/pm.h b/include/linux/pm.h
index d915d0345fa1beb770a742e82247916c440e9543..72c0fe098a27871aa1ea44ea0076d45ab696ea2e 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -93,13 +93,23 @@ typedef struct pm_message {
* been registered) to recover from the race condition.
* This method is executed for all kinds of suspend transitions and is
* followed by one of the suspend callbacks: @suspend(), @freeze(), or
- * @poweroff(). The PM core executes subsystem-level @prepare() for all
- * devices before starting to invoke suspend callbacks for any of them, so
- * generally devices may be assumed to be functional or to respond to
- * runtime resume requests while @prepare() is being executed. However,
- * device drivers may NOT assume anything about the availability of user
- * space at that time and it is NOT valid to request firmware from within
- * @prepare() (it's too late to do that). It also is NOT valid to allocate
+ * @poweroff(). If the transition is a suspend to memory or standby (that
+ * is, not related to hibernation), the return value of @prepare() may be
+ * used to indicate to the PM core to leave the device in runtime suspend
+ * if applicable. Namely, if @prepare() returns a positive number, the PM
+ * core will understand that as a declaration that the device appears to be
+ * runtime-suspended and it may be left in that state during the entire
+ * transition and during the subsequent resume if all of its descendants
+ * are left in runtime suspend too. If that happens, @complete() will be
+ * executed directly after @prepare() and it must ensure the proper
+ * functioning of the device after the system resume.
+ * The PM core executes subsystem-level @prepare() for all devices before
+ * starting to invoke suspend callbacks for any of them, so generally
+ * devices may be assumed to be functional or to respond to runtime resume
+ * requests while @prepare() is being executed. However, device drivers
+ * may NOT assume anything about the availability of user space at that
+ * time and it is NOT valid to request firmware from within @prepare()
+ * (it's too late to do that). It also is NOT valid to allocate
* substantial amounts of memory from @prepare() in the GFP_KERNEL mode.
* [To work around these limitations, drivers may register suspend and
* hibernation notifiers to be executed before the freezing of tasks.]
@@ -112,7 +122,16 @@ typedef struct pm_message {
* of the other devices that the PM core has unsuccessfully attempted to
* suspend earlier).
* The PM core executes subsystem-level @complete() after it has executed
- * the appropriate resume callbacks for all devices.
+ * the appropriate resume callbacks for all devices. If the corresponding
+ * @prepare() at the beginning of the suspend transition returned a
+ * positive number and the device was left in runtime suspend (without
+ * executing any suspend and resume callbacks for it), @complete() will be
+ * the only callback executed for the device during resume. In that case,
+ * @complete() must be prepared to do whatever is necessary to ensure the
+ * proper functioning of the device after the system resume. To this end,
+ * @complete() can check the power.direct_complete flag of the device to
+ * learn whether (unset) or not (set) the previous suspend and resume
+ * callbacks have been executed for it.
*
* @suspend: Executed before putting the system into a sleep state in which the
* contents of main memory are preserved. The exact action to perform
@@ -546,6 +565,7 @@ struct dev_pm_info {
bool is_late_suspended:1;
bool ignore_children:1;
bool early_init:1; /* Owned by the PM core */
+ bool direct_complete:1; /* Owned by the PM core */
spinlock_t lock;
#ifdef CONFIG_PM_SLEEP
struct list_head entry;
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
index 2a5897a4afbc29e8eb52ce45f808fb4fc3107821..43fd6716f66207bc824b94f1fdbfb44bc37d3534 100644
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -101,6 +101,11 @@ static inline bool pm_runtime_status_suspended(struct device *dev)
return dev->power.runtime_status == RPM_SUSPENDED;
}
+static inline bool pm_runtime_suspended_if_enabled(struct device *dev)
+{
+ return pm_runtime_status_suspended(dev) && dev->power.disable_depth == 1;
+}
+
static inline bool pm_runtime_enabled(struct device *dev)
{
return !dev->power.disable_depth;
@@ -150,6 +155,7 @@ static inline void device_set_run_wake(struct device *dev, bool enable) {}
static inline bool pm_runtime_suspended(struct device *dev) { return false; }
static inline bool pm_runtime_active(struct device *dev) { return true; }
static inline bool pm_runtime_status_suspended(struct device *dev) { return false; }
+static inline bool pm_runtime_suspended_if_enabled(struct device *dev) { return false; }
static inline bool pm_runtime_enabled(struct device *dev) { return false; }
static inline void pm_runtime_no_callbacks(struct device *dev) {}