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Diffstat (limited to 'drivers/base/power/runtime.c')
-rw-r--r--drivers/base/power/runtime.c84
1 files changed, 37 insertions, 47 deletions
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 6e89b51ea3d9..8bef3cb2424d 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1613,22 +1613,34 @@ void pm_runtime_drop_link(struct device *dev)
spin_unlock_irq(&dev->power.lock);
}
+static bool pm_runtime_need_not_resume(struct device *dev)
+{
+ return atomic_read(&dev->power.usage_count) <= 1 &&
+ (atomic_read(&dev->power.child_count) == 0 ||
+ dev->power.ignore_children);
+}
+
/**
* pm_runtime_force_suspend - Force a device into suspend state if needed.
* @dev: Device to suspend.
*
* Disable runtime PM so we safely can check the device's runtime PM status and
- * if it is active, invoke it's .runtime_suspend callback to bring it into
- * suspend state. Keep runtime PM disabled to preserve the state unless we
- * encounter errors.
+ * if it is active, invoke its ->runtime_suspend callback to suspend it and
+ * change its runtime PM status field to RPM_SUSPENDED. Also, if the device's
+ * usage and children counters don't indicate that the device was in use before
+ * the system-wide transition under way, decrement its parent's children counter
+ * (if there is a parent). Keep runtime PM disabled to preserve the state
+ * unless we encounter errors.
*
* Typically this function may be invoked from a system suspend callback to make
- * sure the device is put into low power state.
+ * sure the device is put into low power state and it should only be used during
+ * system-wide PM transitions to sleep states. It assumes that the analogous
+ * pm_runtime_force_resume() will be used to resume the device.
*/
int pm_runtime_force_suspend(struct device *dev)
{
int (*callback)(struct device *);
- int ret = 0;
+ int ret;
pm_runtime_disable(dev);
if (pm_runtime_status_suspended(dev))
@@ -1636,27 +1648,23 @@ int pm_runtime_force_suspend(struct device *dev)
callback = RPM_GET_CALLBACK(dev, runtime_suspend);
- if (!callback) {
- ret = -ENOSYS;
- goto err;
- }
-
- ret = callback(dev);
+ ret = callback ? callback(dev) : 0;
if (ret)
goto err;
/*
- * Increase the runtime PM usage count for the device's parent, in case
- * when we find the device being used when system suspend was invoked.
- * This informs pm_runtime_force_resume() to resume the parent
- * immediately, which is needed to be able to resume its children,
- * when not deferring the resume to be managed via runtime PM.
+ * If the device can stay in suspend after the system-wide transition
+ * to the working state that will follow, drop the children counter of
+ * its parent, but set its status to RPM_SUSPENDED anyway in case this
+ * function will be called again for it in the meantime.
*/
- if (dev->parent && atomic_read(&dev->power.usage_count) > 1)
- pm_runtime_get_noresume(dev->parent);
+ if (pm_runtime_need_not_resume(dev))
+ pm_runtime_set_suspended(dev);
+ else
+ __update_runtime_status(dev, RPM_SUSPENDED);
- pm_runtime_set_suspended(dev);
return 0;
+
err:
pm_runtime_enable(dev);
return ret;
@@ -1669,13 +1677,9 @@ EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
*
* Prior invoking this function we expect the user to have brought the device
* into low power state by a call to pm_runtime_force_suspend(). Here we reverse
- * those actions and brings the device into full power, if it is expected to be
- * used on system resume. To distinguish that, we check whether the runtime PM
- * usage count is greater than 1 (the PM core increases the usage count in the
- * system PM prepare phase), as that indicates a real user (such as a subsystem,
- * driver, userspace, etc.) is using it. If that is the case, the device is
- * expected to be used on system resume as well, so then we resume it. In the
- * other case, we defer the resume to be managed via runtime PM.
+ * those actions and bring the device into full power, if it is expected to be
+ * used on system resume. In the other case, we defer the resume to be managed
+ * via runtime PM.
*
* Typically this function may be invoked from a system resume callback.
*/
@@ -1684,32 +1688,18 @@ int pm_runtime_force_resume(struct device *dev)
int (*callback)(struct device *);
int ret = 0;
- callback = RPM_GET_CALLBACK(dev, runtime_resume);
-
- if (!callback) {
- ret = -ENOSYS;
- goto out;
- }
-
- if (!pm_runtime_status_suspended(dev))
+ if (!pm_runtime_status_suspended(dev) || pm_runtime_need_not_resume(dev))
goto out;
/*
- * Decrease the parent's runtime PM usage count, if we increased it
- * during system suspend in pm_runtime_force_suspend().
- */
- if (atomic_read(&dev->power.usage_count) > 1) {
- if (dev->parent)
- pm_runtime_put_noidle(dev->parent);
- } else {
- goto out;
- }
+ * The value of the parent's children counter is correct already, so
+ * just update the status of the device.
+ */
+ __update_runtime_status(dev, RPM_ACTIVE);
- ret = pm_runtime_set_active(dev);
- if (ret)
- goto out;
+ callback = RPM_GET_CALLBACK(dev, runtime_resume);
- ret = callback(dev);
+ ret = callback ? callback(dev) : 0;
if (ret) {
pm_runtime_set_suspended(dev);
goto out;