[PATCH 0/2] Small runtime PM API changes

[PATCH 0/2] Small runtime PM API changes

[Sakari Ailus]

Hi folks,

Here's a small but a different set of patches for making two relatively
minor changes to runtime PM API. I restarted version numbering as this is
meaningfully different from the previous set.

pm_runtime_get_if_active() loses its second argument as it only made sense
to have ign_usage_count argument true.

The other change is also small but it has an effect on callers:
pm_runtime_put_autosuspend() will, in the future, be re-purposed to
include a call to pm_runtime_mark_last_busy() as well. Before this,
current users of the function are moved to __pm_runtime_put_autosuspend()
(added by this patchset) which will continue to have the current
behaviour.

I haven't included the conversion patches in this set as I only want to do
that once this set has been approved and merged. The tree specific patches
can be found here, on linux-next master (there are some V4L2 patches
there, too, please ignore them for now):
<URL:https://git.kernel.org/pub/scm/linux/kernel/git/sailus/linux-next.git/log/?h=pm>

Later on, users calling pm_runtime_mark_last_busy() immediately followed
by __pm_runtime_put_autosuspend() will be switched back to
pm_runtime_put_autosuspend() once its behaviour change has been done (a
patch near top of that branch). I'll provide these once the preceding ones
have been merged.

Comments are welcome.

Sakari Ailus (2):
  pm: runtime: Simplify pm_runtime_get_if_active() usage
  pm: runtime: Add pm_runtime_put_autosuspend() replacement

 Documentation/power/runtime_pm.rst      | 22 ++++++++-----
 drivers/accel/ivpu/ivpu_pm.c            |  2 +-
 drivers/base/power/runtime.c            |  9 +++--
 drivers/gpu/drm/i915/intel_runtime_pm.c |  2 +-
 drivers/gpu/drm/xe/xe_pm.c              |  2 +-
 drivers/media/i2c/ccs/ccs-core.c        |  2 +-
 drivers/media/i2c/ov64a40.c             |  2 +-
 drivers/media/i2c/thp7312.c             |  2 +-
 drivers/net/ipa/ipa_smp2p.c             |  2 +-
 drivers/pci/pci.c                       |  2 +-
 include/linux/pm_runtime.h              | 44 ++++++++++++++++++++++---
 sound/hda/hdac_device.c                 |  2 +-
 12 files changed, 67 insertions(+), 26 deletions(-)

-- 
2.39.2

[PATCH 2/2] pm: runtime: Add pm_runtime_put_autosuspend() replacement

[Sakari Ailus]

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: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 Documentation/power/runtime_pm.rst | 17 +++++++++++------
 include/linux/pm_runtime.h         | 12 ++++++++++++
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/Documentation/power/runtime_pm.rst b/Documentation/power/runtime_pm.rst
index da99379071a4..6fa50e4f87ce 100644
--- a/Documentation/power/runtime_pm.rst
+++ b/Documentation/power/runtime_pm.rst
@@ -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);
 		}
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
index 13cd526634c1..d28df13ffe4d 100644
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -482,6 +482,18 @@ 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.
-- 
2.39.2

[PATCH 1/2] pm: runtime: Simplify pm_runtime_get_if_active() usage

[Sakari Ailus]

There are two ways to opportunistically increment a device's runtime PM
usage count, calling either pm_runtime_get_if_active() or
pm_runtime_get_if_in_use(). The former has an argument to tell whether to
ignore the usage count or not, and the latter simply calls the former with
ign_usage_count set to false. The other users that want to ignore the
usage_count will have to explitly set that argument to true which is a bit
cumbersome.

To make this function more practical to use, remove the ign_usage_count
argument from the function. The main implementation is renamed as
__pm_runtime_get_conditional().

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 Documentation/power/runtime_pm.rst      |  5 ++--
 drivers/accel/ivpu/ivpu_pm.c            |  2 +-
 drivers/base/power/runtime.c            |  9 ++++---
 drivers/gpu/drm/i915/intel_runtime_pm.c |  2 +-
 drivers/gpu/drm/xe/xe_pm.c              |  2 +-
 drivers/media/i2c/ccs/ccs-core.c        |  2 +-
 drivers/media/i2c/ov64a40.c             |  2 +-
 drivers/media/i2c/thp7312.c             |  2 +-
 drivers/net/ipa/ipa_smp2p.c             |  2 +-
 drivers/pci/pci.c                       |  2 +-
 include/linux/pm_runtime.h              | 32 +++++++++++++++++++++----
 sound/hda/hdac_device.c                 |  2 +-
 12 files changed, 44 insertions(+), 20 deletions(-)

diff --git a/Documentation/power/runtime_pm.rst b/Documentation/power/runtime_pm.rst
index 65b86e487afe..da99379071a4 100644
--- a/Documentation/power/runtime_pm.rst
+++ b/Documentation/power/runtime_pm.rst
@@ -396,10 +396,9 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h:
       nonzero, increment the counter and return 1; otherwise return 0 without
       changing the counter
 
-  `int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count);`
+  `int pm_runtime_get_if_active(struct device *dev);`
     - return -EINVAL if 'power.disable_depth' is nonzero; otherwise, if the
-      runtime PM status is RPM_ACTIVE, and either ign_usage_count is true
-      or the device's usage_count is non-zero, increment the counter and
+      runtime PM status is RPM_ACTIVE, increment the counter and
       return 1; otherwise return 0 without changing the counter
 
   `void pm_runtime_put_noidle(struct device *dev);`
diff --git a/drivers/accel/ivpu/ivpu_pm.c b/drivers/accel/ivpu/ivpu_pm.c
index 0af8864cb3b5..c6d93c7a1c58 100644
--- a/drivers/accel/ivpu/ivpu_pm.c
+++ b/drivers/accel/ivpu/ivpu_pm.c
@@ -292,7 +292,7 @@ int ivpu_rpm_get_if_active(struct ivpu_device *vdev)
 {
 	int ret;
 
-	ret = pm_runtime_get_if_active(vdev->drm.dev, false);
+	ret = pm_runtime_get_if_in_use(vdev->drm.dev);
 	drm_WARN_ON(&vdev->drm, ret < 0);
 
 	return ret;
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 05793c9fbb84..6af8e67ab9c7 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1176,7 +1176,7 @@ int __pm_runtime_resume(struct device *dev, int rpmflags)
 EXPORT_SYMBOL_GPL(__pm_runtime_resume);
 
 /**
- * pm_runtime_get_if_active - Conditionally bump up device usage counter.
+ * __pm_runtime_get_conditional - Conditionally bump up device usage counter.
  * @dev: Device to handle.
  * @ign_usage_count: Whether or not to look at the current usage counter value.
  *
@@ -1196,8 +1196,11 @@ EXPORT_SYMBOL_GPL(__pm_runtime_resume);
  *
  * The caller is responsible for decrementing the runtime PM usage counter of
  * @dev after this function has returned a positive value for it.
+ *
+ * This function is not intended to be called by drivers, use
+ * pm_runtime_get_if_active() or pm_runtime_get_if_in_use() instead.
  */
-int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count)
+int __pm_runtime_get_conditional(struct device *dev, bool ign_usage_count)
 {
 	unsigned long flags;
 	int retval;
@@ -1218,7 +1221,7 @@ int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count)
 
 	return retval;
 }
-EXPORT_SYMBOL_GPL(pm_runtime_get_if_active);
+EXPORT_SYMBOL_GPL(__pm_runtime_get_conditional);
 
 /**
  * __pm_runtime_set_status - Set runtime PM status of a device.
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 860b51b56a92..51cbca330bd5 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -246,7 +246,7 @@ static intel_wakeref_t __intel_runtime_pm_get_if_active(struct intel_runtime_pm
 		 * function, since the power state is undefined. This applies
 		 * atm to the late/early system suspend/resume handlers.
 		 */
-		if (pm_runtime_get_if_active(rpm->kdev, ignore_usecount) <= 0)
+		if (__pm_runtime_get_conditional(rpm->kdev, ignore_usecount) <= 0)
 			return 0;
 	}
 
diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
index b429c2876a76..dd110058bf74 100644
--- a/drivers/gpu/drm/xe/xe_pm.c
+++ b/drivers/gpu/drm/xe/xe_pm.c
@@ -330,7 +330,7 @@ int xe_pm_runtime_put(struct xe_device *xe)
 
 int xe_pm_runtime_get_if_active(struct xe_device *xe)
 {
-	return pm_runtime_get_if_active(xe->drm.dev, true);
+	return pm_runtime_get_if_active(xe->drm.dev);
 }
 
 void xe_pm_assert_unbounded_bridge(struct xe_device *xe)
diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
index e21287d50c15..e1ae0f9fad43 100644
--- a/drivers/media/i2c/ccs/ccs-core.c
+++ b/drivers/media/i2c/ccs/ccs-core.c
@@ -674,7 +674,7 @@ static int ccs_set_ctrl(struct v4l2_ctrl *ctrl)
 		break;
 	}
 
-	pm_status = pm_runtime_get_if_active(&client->dev, true);
+	pm_status = pm_runtime_get_if_active(&client->dev);
 	if (!pm_status)
 		return 0;
 
diff --git a/drivers/media/i2c/ov64a40.c b/drivers/media/i2c/ov64a40.c
index 4fba4c2cb064..541bf74581d2 100644
--- a/drivers/media/i2c/ov64a40.c
+++ b/drivers/media/i2c/ov64a40.c
@@ -3287,7 +3287,7 @@ static int ov64a40_set_ctrl(struct v4l2_ctrl *ctrl)
 					 exp_max, 1, exp_val);
 	}
 
-	pm_status = pm_runtime_get_if_active(ov64a40->dev, true);
+	pm_status = pm_runtime_get_if_active(ov64a40->dev);
 	if (!pm_status)
 		return 0;
 
diff --git a/drivers/media/i2c/thp7312.c b/drivers/media/i2c/thp7312.c
index 2806887514dc..19bd923a7315 100644
--- a/drivers/media/i2c/thp7312.c
+++ b/drivers/media/i2c/thp7312.c
@@ -1052,7 +1052,7 @@ static int thp7312_s_ctrl(struct v4l2_ctrl *ctrl)
 	if (ctrl->flags & V4L2_CTRL_FLAG_INACTIVE)
 		return -EINVAL;
 
-	if (!pm_runtime_get_if_active(thp7312->dev, true))
+	if (!pm_runtime_get_if_active(thp7312->dev))
 		return 0;
 
 	switch (ctrl->id) {
diff --git a/drivers/net/ipa/ipa_smp2p.c b/drivers/net/ipa/ipa_smp2p.c
index 5620dc271fac..cbf3d4761ce3 100644
--- a/drivers/net/ipa/ipa_smp2p.c
+++ b/drivers/net/ipa/ipa_smp2p.c
@@ -92,7 +92,7 @@ static void ipa_smp2p_notify(struct ipa_smp2p *smp2p)
 		return;
 
 	dev = &smp2p->ipa->pdev->dev;
-	smp2p->power_on = pm_runtime_get_if_active(dev, true) > 0;
+	smp2p->power_on = pm_runtime_get_if_active(dev) > 0;
 
 	/* Signal whether the IPA power is enabled */
 	mask = BIT(smp2p->enabled_bit);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index d8f11a078924..f8293ae71389 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2510,7 +2510,7 @@ static void pci_pme_list_scan(struct work_struct *work)
 			 * If the device is in a low power state it
 			 * should not be polled either.
 			 */
-			pm_status = pm_runtime_get_if_active(dev, true);
+			pm_status = pm_runtime_get_if_active(dev);
 			if (!pm_status)
 				continue;
 
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
index 7c9b35448563..13cd526634c1 100644
--- a/include/linux/pm_runtime.h
+++ b/include/linux/pm_runtime.h
@@ -72,7 +72,8 @@ extern int pm_runtime_force_resume(struct device *dev);
 extern int __pm_runtime_idle(struct device *dev, int rpmflags);
 extern int __pm_runtime_suspend(struct device *dev, int rpmflags);
 extern int __pm_runtime_resume(struct device *dev, int rpmflags);
-extern int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count);
+extern int __pm_runtime_get_conditional(struct device *dev,
+					bool ign_usage_count);
 extern int pm_schedule_suspend(struct device *dev, unsigned int delay);
 extern int __pm_runtime_set_status(struct device *dev, unsigned int status);
 extern int pm_runtime_barrier(struct device *dev);
@@ -94,16 +95,33 @@ extern void pm_runtime_release_supplier(struct device_link *link);
 
 extern int devm_pm_runtime_enable(struct device *dev);
 
+/**
+ * pm_runtime_get_if_active - Bump up runtime PM usage counter if the device is
+ *			      in active state
+ * @dev: Target device.
+ *
+ * Increment the runtime PM usage counter of @dev if its runtime PM status is
+ * %RPM_ACTIVE, in which case it returns 1. If the device is in a different
+ * state, 0 is returned. -EINVAL is returned if runtime PM is disabled for the
+ * device.
+ */
+static inline int pm_runtime_get_if_active(struct device *dev)
+{
+	return __pm_runtime_get_conditional(dev, true);
+}
+
 /**
  * pm_runtime_get_if_in_use - Conditionally bump up runtime PM usage counter.
  * @dev: Target device.
  *
  * Increment the runtime PM usage counter of @dev if its runtime PM status is
- * %RPM_ACTIVE and its runtime PM usage counter is greater than 0.
+ * %RPM_ACTIVE and its runtime PM usage counter is greater than 0, in which case
+ * it returns 1. If the device is in a different state or its usage_count is 0,
+ * 0 is returned. -EINVAL is returned if runtime PM is disabled for the device.
  */
 static inline int pm_runtime_get_if_in_use(struct device *dev)
 {
-	return pm_runtime_get_if_active(dev, false);
+	return __pm_runtime_get_conditional(dev, false);
 }
 
 /**
@@ -275,8 +293,12 @@ static inline int pm_runtime_get_if_in_use(struct device *dev)
 {
 	return -EINVAL;
 }
-static inline int pm_runtime_get_if_active(struct device *dev,
-					   bool ign_usage_count)
+static inline int pm_runtime_get_if_active(struct device *dev)
+{
+	return -EINVAL;
+}
+static inline int __pm_runtime_get_conditional(struct device *dev,
+					       bool ign_usage_count)
 {
 	return -EINVAL;
 }
diff --git a/sound/hda/hdac_device.c b/sound/hda/hdac_device.c
index 7f7b67fe1b65..068c16e52dff 100644
--- a/sound/hda/hdac_device.c
+++ b/sound/hda/hdac_device.c
@@ -612,7 +612,7 @@ EXPORT_SYMBOL_GPL(snd_hdac_power_up_pm);
 int snd_hdac_keep_power_up(struct hdac_device *codec)
 {
 	if (!atomic_inc_not_zero(&codec->in_pm)) {
-		int ret = pm_runtime_get_if_active(&codec->dev, true);
+		int ret = pm_runtime_get_if_active(&codec->dev);
 		if (!ret)
 			return -1;
 		if (ret < 0)
-- 
2.39.2

Re: [PATCH 1/2] pm: runtime: Simplify pm_runtime_get_if_active() usage

[Alex Elder]

On 1/9/24 7:36 AM, Sakari Ailus wrote:
> There are two ways to opportunistically increment a device's runtime PM
> usage count, calling either pm_runtime_get_if_active() or
> pm_runtime_get_if_in_use(). The former has an argument to tell whether to
> ignore the usage count or not, and the latter simply calls the former with
> ign_usage_count set to false. The other users that want to ignore the
> usage_count will have to explitly set that argument to true which is a bit
> cumbersome.
> 
> To make this function more practical to use, remove the ign_usage_count
> argument from the function. The main implementation is renamed as
> __pm_runtime_get_conditional().
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

I like it.  For drivers/net/ipa/ipa_smp2p.c:

Reviewed-by: Alex Elder <elder@linaro.org>

> ---
>   Documentation/power/runtime_pm.rst      |  5 ++--
>   drivers/accel/ivpu/ivpu_pm.c            |  2 +-
>   drivers/base/power/runtime.c            |  9 ++++---
>   drivers/gpu/drm/i915/intel_runtime_pm.c |  2 +-
>   drivers/gpu/drm/xe/xe_pm.c              |  2 +-
>   drivers/media/i2c/ccs/ccs-core.c        |  2 +-
>   drivers/media/i2c/ov64a40.c             |  2 +-
>   drivers/media/i2c/thp7312.c             |  2 +-
>   drivers/net/ipa/ipa_smp2p.c             |  2 +-
>   drivers/pci/pci.c                       |  2 +-
>   include/linux/pm_runtime.h              | 32 +++++++++++++++++++++----
>   sound/hda/hdac_device.c                 |  2 +-
>   12 files changed, 44 insertions(+), 20 deletions(-)

. . .

Re: [PATCH 1/2] pm: runtime: Simplify pm_runtime_get_if_active() usage

[Laurent Pinchart]

Hi Sakari,

Thank you for the patch.

On Tue, Jan 09, 2024 at 03:36:57PM +0200, Sakari Ailus wrote:
> There are two ways to opportunistically increment a device's runtime PM
> usage count, calling either pm_runtime_get_if_active() or
> pm_runtime_get_if_in_use(). The former has an argument to tell whether to
> ignore the usage count or not, and the latter simply calls the former with
> ign_usage_count set to false. The other users that want to ignore the
> usage_count will have to explitly set that argument to true which is a bit
> cumbersome.
> 
> To make this function more practical to use, remove the ign_usage_count
> argument from the function. The main implementation is renamed as
> __pm_runtime_get_conditional().
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  Documentation/power/runtime_pm.rst      |  5 ++--
>  drivers/accel/ivpu/ivpu_pm.c            |  2 +-
>  drivers/base/power/runtime.c            |  9 ++++---
>  drivers/gpu/drm/i915/intel_runtime_pm.c |  2 +-
>  drivers/gpu/drm/xe/xe_pm.c              |  2 +-
>  drivers/media/i2c/ccs/ccs-core.c        |  2 +-
>  drivers/media/i2c/ov64a40.c             |  2 +-
>  drivers/media/i2c/thp7312.c             |  2 +-
>  drivers/net/ipa/ipa_smp2p.c             |  2 +-
>  drivers/pci/pci.c                       |  2 +-
>  include/linux/pm_runtime.h              | 32 +++++++++++++++++++++----
>  sound/hda/hdac_device.c                 |  2 +-
>  12 files changed, 44 insertions(+), 20 deletions(-)
> 
> diff --git a/Documentation/power/runtime_pm.rst b/Documentation/power/runtime_pm.rst
> index 65b86e487afe..da99379071a4 100644
> --- a/Documentation/power/runtime_pm.rst
> +++ b/Documentation/power/runtime_pm.rst
> @@ -396,10 +396,9 @@ drivers/base/power/runtime.c and include/linux/pm_runtime.h:
>        nonzero, increment the counter and return 1; otherwise return 0 without
>        changing the counter
>  
> -  `int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count);`
> +  `int pm_runtime_get_if_active(struct device *dev);`
>      - return -EINVAL if 'power.disable_depth' is nonzero; otherwise, if the
> -      runtime PM status is RPM_ACTIVE, and either ign_usage_count is true
> -      or the device's usage_count is non-zero, increment the counter and
> +      runtime PM status is RPM_ACTIVE, increment the counter and
>        return 1; otherwise return 0 without changing the counter
>  
>    `void pm_runtime_put_noidle(struct device *dev);`
> diff --git a/drivers/accel/ivpu/ivpu_pm.c b/drivers/accel/ivpu/ivpu_pm.c
> index 0af8864cb3b5..c6d93c7a1c58 100644
> --- a/drivers/accel/ivpu/ivpu_pm.c
> +++ b/drivers/accel/ivpu/ivpu_pm.c
> @@ -292,7 +292,7 @@ int ivpu_rpm_get_if_active(struct ivpu_device *vdev)
>  {
>  	int ret;
>  
> -	ret = pm_runtime_get_if_active(vdev->drm.dev, false);
> +	ret = pm_runtime_get_if_in_use(vdev->drm.dev);
>  	drm_WARN_ON(&vdev->drm, ret < 0);
>  
>  	return ret;
> diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> index 05793c9fbb84..6af8e67ab9c7 100644
> --- a/drivers/base/power/runtime.c
> +++ b/drivers/base/power/runtime.c
> @@ -1176,7 +1176,7 @@ int __pm_runtime_resume(struct device *dev, int rpmflags)
>  EXPORT_SYMBOL_GPL(__pm_runtime_resume);
>  
>  /**
> - * pm_runtime_get_if_active - Conditionally bump up device usage counter.
> + * __pm_runtime_get_conditional - Conditionally bump up device usage counter.
>   * @dev: Device to handle.
>   * @ign_usage_count: Whether or not to look at the current usage counter value.
>   *
> @@ -1196,8 +1196,11 @@ EXPORT_SYMBOL_GPL(__pm_runtime_resume);
>   *
>   * The caller is responsible for decrementing the runtime PM usage counter of
>   * @dev after this function has returned a positive value for it.
> + *
> + * This function is not intended to be called by drivers, use
> + * pm_runtime_get_if_active() or pm_runtime_get_if_in_use() instead.
>   */
> -int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count)
> +int __pm_runtime_get_conditional(struct device *dev, bool ign_usage_count)
>  {
>  	unsigned long flags;
>  	int retval;
> @@ -1218,7 +1221,7 @@ int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count)
>  
>  	return retval;
>  }
> -EXPORT_SYMBOL_GPL(pm_runtime_get_if_active);
> +EXPORT_SYMBOL_GPL(__pm_runtime_get_conditional);
>  
>  /**
>   * __pm_runtime_set_status - Set runtime PM status of a device.
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index 860b51b56a92..51cbca330bd5 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -246,7 +246,7 @@ static intel_wakeref_t __intel_runtime_pm_get_if_active(struct intel_runtime_pm
>  		 * function, since the power state is undefined. This applies
>  		 * atm to the late/early system suspend/resume handlers.
>  		 */
> -		if (pm_runtime_get_if_active(rpm->kdev, ignore_usecount) <= 0)
> +		if (__pm_runtime_get_conditional(rpm->kdev, ignore_usecount) <= 0)
>  			return 0;
>  	}
>  
> diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
> index b429c2876a76..dd110058bf74 100644
> --- a/drivers/gpu/drm/xe/xe_pm.c
> +++ b/drivers/gpu/drm/xe/xe_pm.c
> @@ -330,7 +330,7 @@ int xe_pm_runtime_put(struct xe_device *xe)
>  
>  int xe_pm_runtime_get_if_active(struct xe_device *xe)
>  {
> -	return pm_runtime_get_if_active(xe->drm.dev, true);
> +	return pm_runtime_get_if_active(xe->drm.dev);
>  }
>  
>  void xe_pm_assert_unbounded_bridge(struct xe_device *xe)
> diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
> index e21287d50c15..e1ae0f9fad43 100644
> --- a/drivers/media/i2c/ccs/ccs-core.c
> +++ b/drivers/media/i2c/ccs/ccs-core.c
> @@ -674,7 +674,7 @@ static int ccs_set_ctrl(struct v4l2_ctrl *ctrl)
>  		break;
>  	}
>  
> -	pm_status = pm_runtime_get_if_active(&client->dev, true);
> +	pm_status = pm_runtime_get_if_active(&client->dev);
>  	if (!pm_status)
>  		return 0;
>  
> diff --git a/drivers/media/i2c/ov64a40.c b/drivers/media/i2c/ov64a40.c
> index 4fba4c2cb064..541bf74581d2 100644
> --- a/drivers/media/i2c/ov64a40.c
> +++ b/drivers/media/i2c/ov64a40.c
> @@ -3287,7 +3287,7 @@ static int ov64a40_set_ctrl(struct v4l2_ctrl *ctrl)
>  					 exp_max, 1, exp_val);
>  	}
>  
> -	pm_status = pm_runtime_get_if_active(ov64a40->dev, true);
> +	pm_status = pm_runtime_get_if_active(ov64a40->dev);
>  	if (!pm_status)
>  		return 0;
>  
> diff --git a/drivers/media/i2c/thp7312.c b/drivers/media/i2c/thp7312.c
> index 2806887514dc..19bd923a7315 100644
> --- a/drivers/media/i2c/thp7312.c
> +++ b/drivers/media/i2c/thp7312.c
> @@ -1052,7 +1052,7 @@ static int thp7312_s_ctrl(struct v4l2_ctrl *ctrl)
>  	if (ctrl->flags & V4L2_CTRL_FLAG_INACTIVE)
>  		return -EINVAL;
>  
> -	if (!pm_runtime_get_if_active(thp7312->dev, true))
> +	if (!pm_runtime_get_if_active(thp7312->dev))
>  		return 0;
>  
>  	switch (ctrl->id) {
> diff --git a/drivers/net/ipa/ipa_smp2p.c b/drivers/net/ipa/ipa_smp2p.c
> index 5620dc271fac..cbf3d4761ce3 100644
> --- a/drivers/net/ipa/ipa_smp2p.c
> +++ b/drivers/net/ipa/ipa_smp2p.c
> @@ -92,7 +92,7 @@ static void ipa_smp2p_notify(struct ipa_smp2p *smp2p)
>  		return;
>  
>  	dev = &smp2p->ipa->pdev->dev;
> -	smp2p->power_on = pm_runtime_get_if_active(dev, true) > 0;
> +	smp2p->power_on = pm_runtime_get_if_active(dev) > 0;
>  
>  	/* Signal whether the IPA power is enabled */
>  	mask = BIT(smp2p->enabled_bit);
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index d8f11a078924..f8293ae71389 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -2510,7 +2510,7 @@ static void pci_pme_list_scan(struct work_struct *work)
>  			 * If the device is in a low power state it
>  			 * should not be polled either.
>  			 */
> -			pm_status = pm_runtime_get_if_active(dev, true);
> +			pm_status = pm_runtime_get_if_active(dev);
>  			if (!pm_status)
>  				continue;
>  
> diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
> index 7c9b35448563..13cd526634c1 100644
> --- a/include/linux/pm_runtime.h
> +++ b/include/linux/pm_runtime.h
> @@ -72,7 +72,8 @@ extern int pm_runtime_force_resume(struct device *dev);
>  extern int __pm_runtime_idle(struct device *dev, int rpmflags);
>  extern int __pm_runtime_suspend(struct device *dev, int rpmflags);
>  extern int __pm_runtime_resume(struct device *dev, int rpmflags);
> -extern int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count);
> +extern int __pm_runtime_get_conditional(struct device *dev,
> +					bool ign_usage_count);
>  extern int pm_schedule_suspend(struct device *dev, unsigned int delay);
>  extern int __pm_runtime_set_status(struct device *dev, unsigned int status);
>  extern int pm_runtime_barrier(struct device *dev);
> @@ -94,16 +95,33 @@ extern void pm_runtime_release_supplier(struct device_link *link);
>  
>  extern int devm_pm_runtime_enable(struct device *dev);
>  
> +/**
> + * pm_runtime_get_if_active - Bump up runtime PM usage counter if the device is
> + *			      in active state
> + * @dev: Target device.
> + *
> + * Increment the runtime PM usage counter of @dev if its runtime PM status is
> + * %RPM_ACTIVE, in which case it returns 1. If the device is in a different
> + * state, 0 is returned. -EINVAL is returned if runtime PM is disabled for the
> + * device.
> + */
> +static inline int pm_runtime_get_if_active(struct device *dev)
> +{
> +	return __pm_runtime_get_conditional(dev, true);
> +}
> +
>  /**
>   * pm_runtime_get_if_in_use - Conditionally bump up runtime PM usage counter.
>   * @dev: Target device.
>   *
>   * Increment the runtime PM usage counter of @dev if its runtime PM status is
> - * %RPM_ACTIVE and its runtime PM usage counter is greater than 0.
> + * %RPM_ACTIVE and its runtime PM usage counter is greater than 0, in which case
> + * it returns 1. If the device is in a different state or its usage_count is 0,
> + * 0 is returned. -EINVAL is returned if runtime PM is disabled for the device.
>   */
>  static inline int pm_runtime_get_if_in_use(struct device *dev)
>  {
> -	return pm_runtime_get_if_active(dev, false);
> +	return __pm_runtime_get_conditional(dev, false);
>  }
>  
>  /**
> @@ -275,8 +293,12 @@ static inline int pm_runtime_get_if_in_use(struct device *dev)
>  {
>  	return -EINVAL;
>  }
> -static inline int pm_runtime_get_if_active(struct device *dev,
> -					   bool ign_usage_count)
> +static inline int pm_runtime_get_if_active(struct device *dev)
> +{
> +	return -EINVAL;
> +}
> +static inline int __pm_runtime_get_conditional(struct device *dev,
> +					       bool ign_usage_count)
>  {
>  	return -EINVAL;
>  }
> diff --git a/sound/hda/hdac_device.c b/sound/hda/hdac_device.c
> index 7f7b67fe1b65..068c16e52dff 100644
> --- a/sound/hda/hdac_device.c
> +++ b/sound/hda/hdac_device.c
> @@ -612,7 +612,7 @@ EXPORT_SYMBOL_GPL(snd_hdac_power_up_pm);
>  int snd_hdac_keep_power_up(struct hdac_device *codec)
>  {
>  	if (!atomic_inc_not_zero(&codec->in_pm)) {
> -		int ret = pm_runtime_get_if_active(&codec->dev, true);
> +		int ret = pm_runtime_get_if_active(&codec->dev);
>  		if (!ret)
>  			return -1;
>  		if (ret < 0)

-- 
Regards,

Laurent Pinchart

Re: [PATCH 2/2] pm: runtime: Add pm_runtime_put_autosuspend() replacement

[Laurent Pinchart]

Hi Sakari,

Thank you for the patch.

On Tue, Jan 09, 2024 at 03:36:39PM +0200, Sakari Ailus wrote:
> 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: Sakari Ailus <sakari.ailus@linux.intel.com>

This looks good to me, so

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Do you plan to patch the existing users tree-wide ?

> ---
>  Documentation/power/runtime_pm.rst | 17 +++++++++++------
>  include/linux/pm_runtime.h         | 12 ++++++++++++
>  2 files changed, 23 insertions(+), 6 deletions(-)
> 
> diff --git a/Documentation/power/runtime_pm.rst b/Documentation/power/runtime_pm.rst
> index da99379071a4..6fa50e4f87ce 100644
> --- a/Documentation/power/runtime_pm.rst
> +++ b/Documentation/power/runtime_pm.rst
> @@ -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);
>  		}
> diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
> index 13cd526634c1..d28df13ffe4d 100644
> --- a/include/linux/pm_runtime.h
> +++ b/include/linux/pm_runtime.h
> @@ -482,6 +482,18 @@ 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.

-- 
Regards,

Laurent Pinchart

Re: [PATCH 1/2] pm: runtime: Simplify pm_runtime_get_if_active() usage

[Takashi Iwai]

On Tue, 09 Jan 2024 14:36:57 +0100,
Sakari Ailus wrote:
> 
> There are two ways to opportunistically increment a device's runtime PM
> usage count, calling either pm_runtime_get_if_active() or
> pm_runtime_get_if_in_use(). The former has an argument to tell whether to
> ignore the usage count or not, and the latter simply calls the former with
> ign_usage_count set to false. The other users that want to ignore the
> usage_count will have to explitly set that argument to true which is a bit
> cumbersome.
> 
> To make this function more practical to use, remove the ign_usage_count
> argument from the function. The main implementation is renamed as
> __pm_runtime_get_conditional().
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
>  Documentation/power/runtime_pm.rst      |  5 ++--
>  drivers/accel/ivpu/ivpu_pm.c            |  2 +-
>  drivers/base/power/runtime.c            |  9 ++++---
>  drivers/gpu/drm/i915/intel_runtime_pm.c |  2 +-
>  drivers/gpu/drm/xe/xe_pm.c              |  2 +-
>  drivers/media/i2c/ccs/ccs-core.c        |  2 +-
>  drivers/media/i2c/ov64a40.c             |  2 +-
>  drivers/media/i2c/thp7312.c             |  2 +-
>  drivers/net/ipa/ipa_smp2p.c             |  2 +-
>  drivers/pci/pci.c                       |  2 +-
>  include/linux/pm_runtime.h              | 32 +++++++++++++++++++++----
>  sound/hda/hdac_device.c                 |  2 +-

For sound/*,

Acked-by: Takashi Iwai <tiwai@suse.de>


thanks,

Takashi

Re: [PATCH 1/2] pm: runtime: Simplify pm_runtime_get_if_active() usage

[Jacek Lawrynowicz]

On 09.01.2024 14:36, Sakari Ailus wrote:
> There are two ways to opportunistically increment a device's runtime PM
> usage count, calling either pm_runtime_get_if_active() or
> pm_runtime_get_if_in_use(). The former has an argument to tell whether to
> ignore the usage count or not, and the latter simply calls the former with
> ign_usage_count set to false. The other users that want to ignore the
> usage_count will have to explitly set that argument to true which is a bit
> cumbersome.
> 
> To make this function more practical to use, remove the ign_usage_count
> argument from the function. The main implementation is renamed as
> __pm_runtime_get_conditional().
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---

For drivers/accel/ivpu:

Reviewed-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>

Thanks,
Jacek

Re: [PATCH 1/2] pm: runtime: Simplify pm_runtime_get_if_active() usage

[Rodrigo Vivi]

On Tue, Jan 09, 2024 at 03:36:57PM +0200, Sakari Ailus wrote:
> There are two ways to opportunistically increment a device's runtime PM
> usage count, calling either pm_runtime_get_if_active() or
> pm_runtime_get_if_in_use(). The former has an argument to tell whether to
> ignore the usage count or not, and the latter simply calls the former with
> ign_usage_count set to false. The other users that want to ignore the
> usage_count will have to explitly set that argument to true which is a bit
> cumbersome.
> 
> To make this function more practical to use, remove the ign_usage_count
> argument from the function. The main implementation is renamed as
> __pm_runtime_get_conditional().

Great idea! I recently found a bug in Xe caused by some confusion
with the ign_usage_count var.

> + * This function is not intended to be called by drivers, use
> + * pm_runtime_get_if_active() or pm_runtime_get_if_in_use() instead.
>   */

Well, it is not intended, but we already have an usage for that.
So, shouldn't we avoid the '__' and just put as recommendation?
Like we have around the get_sync telling that the preferred way is
the resume_and_get for a cleaner code?

> -EXPORT_SYMBOL_GPL(pm_runtime_get_if_active);
> +EXPORT_SYMBOL_GPL(__pm_runtime_get_conditional);

Also the '__' in the exported and documented one doesn't look so nice.
Well, I know that this would be the case even without any driver using
because of the static inline anyway.

>  
>  /**
>   * __pm_runtime_set_status - Set runtime PM status of a device.
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index 860b51b56a92..51cbca330bd5 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -246,7 +246,7 @@ static intel_wakeref_t __intel_runtime_pm_get_if_active(struct intel_runtime_pm
>  		 * function, since the power state is undefined. This applies
>  		 * atm to the late/early system suspend/resume handlers.
>  		 */
> -		if (pm_runtime_get_if_active(rpm->kdev, ignore_usecount) <= 0)
> +		if (__pm_runtime_get_conditional(rpm->kdev, ignore_usecount) <= 0)

Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

>  			return 0;
>  	}
>  
> diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
> index b429c2876a76..dd110058bf74 100644
> --- a/drivers/gpu/drm/xe/xe_pm.c
> +++ b/drivers/gpu/drm/xe/xe_pm.c
> @@ -330,7 +330,7 @@ int xe_pm_runtime_put(struct xe_device *xe)
>  
>  int xe_pm_runtime_get_if_active(struct xe_device *xe)
>  {
> -	return pm_runtime_get_if_active(xe->drm.dev, true);
> +	return pm_runtime_get_if_active(xe->drm.dev);
>  }
>  
>  void xe_pm_assert_unbounded_bridge(struct xe_device *xe)
> diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs-core.c
> index e21287d50c15..e1ae0f9fad43 100644
> --- a/drivers/media/i2c/ccs/ccs-core.c
> +++ b/drivers/media/i2c/ccs/ccs-core.c
> @@ -674,7 +674,7 @@ static int ccs_set_ctrl(struct v4l2_ctrl *ctrl)
>  		break;
>  	}
>  
> -	pm_status = pm_runtime_get_if_active(&client->dev, true);
> +	pm_status = pm_runtime_get_if_active(&client->dev);
>  	if (!pm_status)
>  		return 0;
>  
> diff --git a/drivers/media/i2c/ov64a40.c b/drivers/media/i2c/ov64a40.c
> index 4fba4c2cb064..541bf74581d2 100644
> --- a/drivers/media/i2c/ov64a40.c
> +++ b/drivers/media/i2c/ov64a40.c
> @@ -3287,7 +3287,7 @@ static int ov64a40_set_ctrl(struct v4l2_ctrl *ctrl)
>  					 exp_max, 1, exp_val);
>  	}
>  
> -	pm_status = pm_runtime_get_if_active(ov64a40->dev, true);
> +	pm_status = pm_runtime_get_if_active(ov64a40->dev);
>  	if (!pm_status)
>  		return 0;
>  
> diff --git a/drivers/media/i2c/thp7312.c b/drivers/media/i2c/thp7312.c
> index 2806887514dc..19bd923a7315 100644
> --- a/drivers/media/i2c/thp7312.c
> +++ b/drivers/media/i2c/thp7312.c
> @@ -1052,7 +1052,7 @@ static int thp7312_s_ctrl(struct v4l2_ctrl *ctrl)
>  	if (ctrl->flags & V4L2_CTRL_FLAG_INACTIVE)
>  		return -EINVAL;
>  
> -	if (!pm_runtime_get_if_active(thp7312->dev, true))
> +	if (!pm_runtime_get_if_active(thp7312->dev))
>  		return 0;
>  
>  	switch (ctrl->id) {
> diff --git a/drivers/net/ipa/ipa_smp2p.c b/drivers/net/ipa/ipa_smp2p.c
> index 5620dc271fac..cbf3d4761ce3 100644
> --- a/drivers/net/ipa/ipa_smp2p.c
> +++ b/drivers/net/ipa/ipa_smp2p.c
> @@ -92,7 +92,7 @@ static void ipa_smp2p_notify(struct ipa_smp2p *smp2p)
>  		return;
>  
>  	dev = &smp2p->ipa->pdev->dev;
> -	smp2p->power_on = pm_runtime_get_if_active(dev, true) > 0;
> +	smp2p->power_on = pm_runtime_get_if_active(dev) > 0;
>  
>  	/* Signal whether the IPA power is enabled */
>  	mask = BIT(smp2p->enabled_bit);
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index d8f11a078924..f8293ae71389 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -2510,7 +2510,7 @@ static void pci_pme_list_scan(struct work_struct *work)
>  			 * If the device is in a low power state it
>  			 * should not be polled either.
>  			 */
> -			pm_status = pm_runtime_get_if_active(dev, true);
> +			pm_status = pm_runtime_get_if_active(dev);
>  			if (!pm_status)
>  				continue;
>  
> diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h
> index 7c9b35448563..13cd526634c1 100644
> --- a/include/linux/pm_runtime.h
> +++ b/include/linux/pm_runtime.h
> @@ -72,7 +72,8 @@ extern int pm_runtime_force_resume(struct device *dev);
>  extern int __pm_runtime_idle(struct device *dev, int rpmflags);
>  extern int __pm_runtime_suspend(struct device *dev, int rpmflags);
>  extern int __pm_runtime_resume(struct device *dev, int rpmflags);
> -extern int pm_runtime_get_if_active(struct device *dev, bool ign_usage_count);
> +extern int __pm_runtime_get_conditional(struct device *dev,
> +					bool ign_usage_count);
>  extern int pm_schedule_suspend(struct device *dev, unsigned int delay);
>  extern int __pm_runtime_set_status(struct device *dev, unsigned int status);
>  extern int pm_runtime_barrier(struct device *dev);
> @@ -94,16 +95,33 @@ extern void pm_runtime_release_supplier(struct device_link *link);
>  
>  extern int devm_pm_runtime_enable(struct device *dev);
>  
> +/**
> + * pm_runtime_get_if_active - Bump up runtime PM usage counter if the device is
> + *			      in active state
> + * @dev: Target device.
> + *
> + * Increment the runtime PM usage counter of @dev if its runtime PM status is
> + * %RPM_ACTIVE, in which case it returns 1. If the device is in a different
> + * state, 0 is returned. -EINVAL is returned if runtime PM is disabled for the
> + * device.
> + */
> +static inline int pm_runtime_get_if_active(struct device *dev)
> +{
> +	return __pm_runtime_get_conditional(dev, true);
> +}
> +
>  /**
>   * pm_runtime_get_if_in_use - Conditionally bump up runtime PM usage counter.
>   * @dev: Target device.
>   *
>   * Increment the runtime PM usage counter of @dev if its runtime PM status is
> - * %RPM_ACTIVE and its runtime PM usage counter is greater than 0.
> + * %RPM_ACTIVE and its runtime PM usage counter is greater than 0, in which case
> + * it returns 1. If the device is in a different state or its usage_count is 0,
> + * 0 is returned. -EINVAL is returned if runtime PM is disabled for the device.
>   */
>  static inline int pm_runtime_get_if_in_use(struct device *dev)
>  {
> -	return pm_runtime_get_if_active(dev, false);
> +	return __pm_runtime_get_conditional(dev, false);
>  }
>  
>  /**
> @@ -275,8 +293,12 @@ static inline int pm_runtime_get_if_in_use(struct device *dev)
>  {
>  	return -EINVAL;
>  }
> -static inline int pm_runtime_get_if_active(struct device *dev,
> -					   bool ign_usage_count)
> +static inline int pm_runtime_get_if_active(struct device *dev)
> +{
> +	return -EINVAL;
> +}
> +static inline int __pm_runtime_get_conditional(struct device *dev,
> +					       bool ign_usage_count)
>  {
>  	return -EINVAL;
>  }
> diff --git a/sound/hda/hdac_device.c b/sound/hda/hdac_device.c
> index 7f7b67fe1b65..068c16e52dff 100644
> --- a/sound/hda/hdac_device.c
> +++ b/sound/hda/hdac_device.c
> @@ -612,7 +612,7 @@ EXPORT_SYMBOL_GPL(snd_hdac_power_up_pm);
>  int snd_hdac_keep_power_up(struct hdac_device *codec)
>  {
>  	if (!atomic_inc_not_zero(&codec->in_pm)) {
> -		int ret = pm_runtime_get_if_active(&codec->dev, true);
> +		int ret = pm_runtime_get_if_active(&codec->dev);
>  		if (!ret)
>  			return -1;
>  		if (ret < 0)
> -- 
> 2.39.2
> 

Re: [PATCH 2/2] pm: runtime: Add pm_runtime_put_autosuspend() replacement

[Sakari Ailus]

Hi Laurent,

On Tue, Jan 09, 2024 at 06:40:47PM +0200, Laurent Pinchart wrote:
> Hi Sakari,
> 
> Thank you for the patch.
> 
> On Tue, Jan 09, 2024 at 03:36:39PM +0200, Sakari Ailus wrote:
> > 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: Sakari Ailus <sakari.ailus@linux.intel.com>
> 
> This looks good to me, so
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> 
> Do you plan to patch the existing users tree-wide ?

As noted on the cover letter, these are found here:
<URL:https://git.kernel.org/pub/scm/linux/kernel/git/sailus/linux-next.git/log/?h=pm>.

-- 
Regards,

Sakari Ailus

Re: [PATCH 1/2] pm: runtime: Simplify pm_runtime_get_if_active() usage

[Sakari Ailus]

Hi Rodrigo,

Thanks for the review.

On Tue, Jan 09, 2024 at 12:35:25PM -0500, Rodrigo Vivi wrote:
> On Tue, Jan 09, 2024 at 03:36:57PM +0200, Sakari Ailus wrote:
> > There are two ways to opportunistically increment a device's runtime PM
> > usage count, calling either pm_runtime_get_if_active() or
> > pm_runtime_get_if_in_use(). The former has an argument to tell whether to
> > ignore the usage count or not, and the latter simply calls the former with
> > ign_usage_count set to false. The other users that want to ignore the
> > usage_count will have to explitly set that argument to true which is a bit
> > cumbersome.
> > 
> > To make this function more practical to use, remove the ign_usage_count
> > argument from the function. The main implementation is renamed as
> > __pm_runtime_get_conditional().
> 
> Great idea! I recently found a bug in Xe caused by some confusion
> with the ign_usage_count var.
> 
> > + * This function is not intended to be called by drivers, use
> > + * pm_runtime_get_if_active() or pm_runtime_get_if_in_use() instead.
> >   */
> 
> Well, it is not intended, but we already have an usage for that.
> So, shouldn't we avoid the '__' and just put as recommendation?
> Like we have around the get_sync telling that the preferred way is
> the resume_and_get for a cleaner code?

I'll do that in v2, it's indeed not an issue to call this directly in a
driver as you have ign_usage_count value available. Which is why the
comment says "intended". Feel free to propose a better wording.

pm_runtime_resume_and_get() isn't a universal replacement for
pm_runtime_get_sync() as pm_runtime_resume_and_get() won't return 1 if the
device was already active---this was considered a possible source of bugs
AFAIR. So there will be drivers using pm_runtime_get_sync().

> 
> > -EXPORT_SYMBOL_GPL(pm_runtime_get_if_active);
> > +EXPORT_SYMBOL_GPL(__pm_runtime_get_conditional);
> 
> Also the '__' in the exported and documented one doesn't look so nice.
> Well, I know that this would be the case even without any driver using
> because of the static inline anyway.
> 
> >  
> >  /**
> >   * __pm_runtime_set_status - Set runtime PM status of a device.
> > diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> > index 860b51b56a92..51cbca330bd5 100644
> > --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> > @@ -246,7 +246,7 @@ static intel_wakeref_t __intel_runtime_pm_get_if_active(struct intel_runtime_pm
> >  		 * function, since the power state is undefined. This applies
> >  		 * atm to the late/early system suspend/resume handlers.
> >  		 */
> > -		if (pm_runtime_get_if_active(rpm->kdev, ignore_usecount) <= 0)
> > +		if (__pm_runtime_get_conditional(rpm->kdev, ignore_usecount) <= 0)
> 
> Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Thanks!

-- 
Regards,

Sakari Ailus

Re: [PATCH 1/2] pm: runtime: Simplify pm_runtime_get_if_active() usage

[Sakari Ailus]

Hi Rodrigo,

On Tue, Jan 09, 2024 at 12:35:25PM -0500, Rodrigo Vivi wrote:
> On Tue, Jan 09, 2024 at 03:36:57PM +0200, Sakari Ailus wrote:
> > There are two ways to opportunistically increment a device's runtime PM
> > usage count, calling either pm_runtime_get_if_active() or
> > pm_runtime_get_if_in_use(). The former has an argument to tell whether to
> > ignore the usage count or not, and the latter simply calls the former with
> > ign_usage_count set to false. The other users that want to ignore the
> > usage_count will have to explitly set that argument to true which is a bit
> > cumbersome.
> > 
> > To make this function more practical to use, remove the ign_usage_count
> > argument from the function. The main implementation is renamed as
> > __pm_runtime_get_conditional().
> 
> Great idea! I recently found a bug in Xe caused by some confusion
> with the ign_usage_count var.
> 
> > + * This function is not intended to be called by drivers, use
> > + * pm_runtime_get_if_active() or pm_runtime_get_if_in_use() instead.
> >   */
> 
> Well, it is not intended, but we already have an usage for that.

I'll change the above text to:

 * This function is not primarily intended for use in drivers, most of which are
 * better served by either pm_runtime_get_if_active() or
 * pm_runtime_get_if_in_use() instead.

Perhaps it would better reflect the intention and actual use.

-- 
Regards,

Sakari Ailus