Commit b7d46644 authored by Sakari Ailus's avatar Sakari Ailus Committed by Rafael J. Wysocki
Browse files

PM: runtime: Add pm_runtime_put_autosuspend() replacement 



Add __pm_runtime_put_autosuspend() that replaces
pm_runtime_put_autosuspend() for new users. The intent is to later
re-purpose pm_runtime_put_autosuspend() to also mark the device's last
busy stamp---which is what the vast majority of users actually need.

This is also described in pm_runtime_put_autosuspend() documentation.

Signed-off-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: default avatarLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent c0ef3df8

Documentation/power/runtime_pm.rst

+11 −6
Original line number Diff line number Diff line
@@ -154,7 +154,7 @@ suspending the device are satisfied) and to queue up a suspend request for the 
device in that case.  If there is no idle callback, or if the callback returns

0, then the PM core will attempt to carry out a runtime suspend of the device,

also respecting devices configured for autosuspend.  In essence this means a

call to pm_runtime_autosuspend() (do note that drivers needs to update the

call to __pm_runtime_autosuspend() (do note that drivers needs to update the

device last busy mark, pm_runtime_mark_last_busy(), to control the delay under

this circumstance).  To prevent this (for example, if the callback routine has

started a delayed suspend), the routine must return a non-zero value.  Negative
@@ -409,6 +409,10 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h: 
      pm_request_idle(dev) and return its result



  `int pm_runtime_put_autosuspend(struct device *dev);`

    - does the same as __pm_runtime_put_autosuspend() for now, but in the

      future, will also call pm_runtime_mark_last_busy() as well, DO NOT USE!



  `int __pm_runtime_put_autosuspend(struct device *dev);`

    - decrement the device's usage counter; if the result is 0 then run

      pm_request_autosuspend(dev) and return its result
@@ -539,6 +543,7 @@ It is safe to execute the following helper functions from interrupt context: 
- pm_runtime_put_noidle()

- pm_runtime_put()

- pm_runtime_put_autosuspend()

- __pm_runtime_put_autosuspend()

- pm_runtime_enable()

- pm_suspend_ignore_children()

- pm_runtime_set_active()
@@ -864,9 +869,9 @@ automatically be delayed until the desired period of inactivity has elapsed. 


Inactivity is determined based on the power.last_busy field.  Drivers should

call pm_runtime_mark_last_busy() to update this field after carrying out I/O,

typically just before calling pm_runtime_put_autosuspend().  The desired length

of the inactivity period is a matter of policy.  Subsystems can set this length

initially by calling pm_runtime_set_autosuspend_delay(), but after device

typically just before calling __pm_runtime_put_autosuspend().  The desired

length of the inactivity period is a matter of policy.  Subsystems can set this

length initially by calling pm_runtime_set_autosuspend_delay(), but after device

registration the length should be controlled by user space, using the

/sys/devices/.../power/autosuspend_delay_ms attribute.
@@ -877,7 +882,7 @@ instead of the non-autosuspend counterparts:: 


	Instead of: pm_runtime_suspend    use: pm_runtime_autosuspend;

	Instead of: pm_schedule_suspend   use: pm_request_autosuspend;

	Instead of: pm_runtime_put        use: pm_runtime_put_autosuspend;

	Instead of: pm_runtime_put        use: __pm_runtime_put_autosuspend;

	Instead of: pm_runtime_put_sync   use: pm_runtime_put_sync_autosuspend.



Drivers may also continue to use the non-autosuspend helper functions; they
@@ -916,7 +921,7 @@ Here is a schematic pseudo-code example:: 
		lock(&foo->private_lock);

		if (--foo->num_pending_requests == 0) {

			pm_runtime_mark_last_busy(&foo->dev);

			pm_runtime_put_autosuspend(&foo->dev);

			__pm_runtime_put_autosuspend(&foo->dev);

		} else {

			foo_process_next_request(foo);

		}

include/linux/pm_runtime.h

+12 −0
Original line number Diff line number Diff line
@@ -448,6 +448,18 @@ static inline int pm_runtime_put(struct device *dev) 
	return __pm_runtime_idle(dev, RPM_GET_PUT | RPM_ASYNC);

}



/**

 * __pm_runtime_put_autosuspend - Drop device usage counter and queue autosuspend if 0.

 * @dev: Target device.

 *

 * Decrement the runtime PM usage counter of @dev and if it turns out to be

 * equal to 0, queue up a work item for @dev like in pm_request_autosuspend().

 */

static inline int __pm_runtime_put_autosuspend(struct device *dev)

{

	return __pm_runtime_suspend(dev, RPM_GET_PUT | RPM_ASYNC | RPM_AUTO);

}



/**

 * pm_runtime_put_autosuspend - Drop device usage counter and queue autosuspend if 0.

 * @dev: Target device.