PM: Rearrange documentation related to __pm_runtime_disable()

JIRA: https://issues.redhat.com/browse/RHEL-80696

commit 258e231
Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Date:   Mon Feb 17 21:03:01 2025 +0100

There are only two callers of __pm_runtime_disable(), one of which is
device_suspend_late() and the other is pm_runtime_disable() that has
its own kerneldoc comment and there are no plans to add any more of
them.  Since they use different values of the __pm_runtime_disable()
second parameter, the actual code behavior is different in each case,
but it is all documented in the __pm_runtime_disable() kerneldoc comment
which is not particularly straightforward.

For this reason, move the information from the __pm_runtime_disable()
kerneldoc comment to the pm_runtime_disable() one and into a separate
comment in device_suspend_late() and remove the __pm_runtime_disable()
kerneldoc comment altogether.

No functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://patch.msgid.link/12617588.O9o76ZdvQC@rjwysocki.net
Signed-off-by: Mark Langsdorf <mlangsdo@redhat.com>

Author: mlangsdorf

drivers/base/power/main.c

@@ -1396,6 +1396,10 @@ static int device_suspend_late(struct device *dev, pm_message_t state, bool asyn
 	TRACE_DEVICE(dev);
 	TRACE_SUSPEND(0);
 
+	/*
+	 * Disable runtime PM for the device without checking if there is a
+	 * pending resume request for it.
+	 */
 	__pm_runtime_disable(dev, false);
 
 	dpm_wait_for_subordinate(dev, async);

drivers/base/power/runtime.c

@@ -1460,20 +1460,6 @@ int pm_runtime_barrier(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(pm_runtime_barrier);
 
-/**
- * __pm_runtime_disable - Disable runtime PM of a device.
- * @dev: Device to handle.
- * @check_resume: If set, check if there's a resume request for the device.
- *
- * Increment power.disable_depth for the device and if it was zero previously,
- * cancel all pending runtime PM requests for the device and wait for all
- * operations in progress to complete.  The device can be either active or
- * suspended after its runtime PM has been disabled.
- *
- * If @check_resume is set and there's a resume request pending when
- * __pm_runtime_disable() is called and power.disable_depth is zero, the
- * function will wake up the device before disabling its runtime PM.
- */
 void __pm_runtime_disable(struct device *dev, bool check_resume)
 {
 	spin_lock_irq(&dev->power.lock);

include/linux/pm_runtime.h

@@ -556,11 +556,18 @@ static inline int pm_runtime_set_suspended(struct device *dev)
  * pm_runtime_disable - Disable runtime PM for a device.
  * @dev: Target device.
  *
- * Prevent the runtime PM framework from working with @dev (by incrementing its
- * "blocking" counter).
- *
- * For each invocation of this function for @dev there must be a matching
- * pm_runtime_enable() call in order for runtime PM to be enabled for it.
+ * Prevent the runtime PM framework from working with @dev by incrementing its
+ * "disable" counter.
+ *
+ * If the counter is zero when this function runs and there is a pending runtime
+ * resume request for @dev, it will be resumed.  If the counter is still zero at
+ * that point, all of the pending runtime PM requests for @dev will be canceled
+ * and all runtime PM operations in progress involving it will be waited for to
+ * complete.
+ *
+ * For each invocation of this function for @dev, there must be a matching
+ * pm_runtime_enable() call, so that runtime PM is eventually enabled for it
+ * again.
  */
 static inline void pm_runtime_disable(struct device *dev)
 {