Recent changes to the PM core allows ->runtime_suspend|resume callbacks to
be unassigned.
In the earlier behaviour the PM core would return -ENOSYS, when trying to
runtime resume a device, for example. Let's update the documentation to
clarify this.
Signed-off-by: Ulf Hansson <redacted>
---
Changes in v4:
- This time, really, fix spelling and further clarified the behaviour,
according to comments from Alan.
---
Documentation/power/runtime_pm.rst | 9 +++++++++
1 file changed, 9 insertions(+)
@@ -827,6 +827,15 @@ or driver about runtime power changes. Instead, the driver for the device's parent must take responsibility for telling the device's driver when the parent's power state changes.+Note that, in some cases it may not be desirable for subsystems/drivers to call+pm_runtime_no_callbacks() for their devices. This could be because a subset of+the runtime PM callbacks needs to be implemented, a platform dependent PM+domain could get attached to the device or that the device is power managed+through a supplier device link. For these reasons and to avoid boilerplate code+in subsystems/drivers, the PM core allows runtime PM callbacks to be+unassigned. More precisely, if a callback pointer is NULL, the PM core will act+as though there was a callback and it returned 0.+9. Autosuspend, or automatically-delayed suspends =================================================
--
2.25.1
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From: Alan Stern <stern@rowland.harvard.edu> Date: 2021-06-09 14:16:28
On Wed, Jun 09, 2021 at 12:06:10PM +0200, Ulf Hansson wrote:
quoted hunk
Recent changes to the PM core allows ->runtime_suspend|resume callbacks to
be unassigned.
In the earlier behaviour the PM core would return -ENOSYS, when trying to
runtime resume a device, for example. Let's update the documentation to
clarify this.
Signed-off-by: Ulf Hansson <redacted>
---
Changes in v4:
- This time, really, fix spelling and further clarified the behaviour,
according to comments from Alan.
---
Documentation/power/runtime_pm.rst | 9 +++++++++
1 file changed, 9 insertions(+)
@@ -827,6 +827,15 @@ or driver about runtime power changes. Instead, the driver for the device's parent must take responsibility for telling the device's driver when the parent's power state changes.+Note that, in some cases it may not be desirable for subsystems/drivers to call+pm_runtime_no_callbacks() for their devices. This could be because a subset of+the runtime PM callbacks needs to be implemented, a platform dependent PM+domain could get attached to the device or that the device is power managed+through a supplier device link. For these reasons and to avoid boilerplate code+in subsystems/drivers, the PM core allows runtime PM callbacks to be+unassigned. More precisely, if a callback pointer is NULL, the PM core will act+as though there was a callback and it returned 0.+9. Autosuspend, or automatically-delayed suspends =================================================
Acked-by: Alan Stern <stern@rowland.harvard.edu>
I don't know what happened before. Maybe the terminal window got
resized without me noticing, so the lines looked too long when they
actually weren't.
Alan Stern
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From: "Rafael J. Wysocki" <rafael@kernel.org> Date: 2021-06-11 17:06:12
On Wed, Jun 9, 2021 at 4:16 PM Alan Stern [off-list ref] wrote:
On Wed, Jun 09, 2021 at 12:06:10PM +0200, Ulf Hansson wrote:
quoted
Recent changes to the PM core allows ->runtime_suspend|resume callbacks to
be unassigned.
In the earlier behaviour the PM core would return -ENOSYS, when trying to
runtime resume a device, for example. Let's update the documentation to
clarify this.
Signed-off-by: Ulf Hansson <redacted>
---
Changes in v4:
- This time, really, fix spelling and further clarified the behaviour,
according to comments from Alan.
---
Documentation/power/runtime_pm.rst | 9 +++++++++
1 file changed, 9 insertions(+)
@@ -827,6 +827,15 @@ or driver about runtime power changes. Instead, the driver for the device's parent must take responsibility for telling the device's driver when the parent's power state changes.+Note that, in some cases it may not be desirable for subsystems/drivers to call+pm_runtime_no_callbacks() for their devices. This could be because a subset of+the runtime PM callbacks needs to be implemented, a platform dependent PM+domain could get attached to the device or that the device is power managed+through a supplier device link. For these reasons and to avoid boilerplate code+in subsystems/drivers, the PM core allows runtime PM callbacks to be+unassigned. More precisely, if a callback pointer is NULL, the PM core will act+as though there was a callback and it returned 0.+9. Autosuspend, or automatically-delayed suspends =================================================
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Applied as 5.14 material along with the [1-2/3] from this series.
Thanks!
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