[PATCH V3] PM / core: fix deferred probe breaking suspend resume order

[Rafael J. Wysocki]

On Monday, March 5, 2018 7:29:39 PM CEST Feng Kan wrote:
> When bridge and its endpoint is enumerated the devices are added to the
> dpm list. Afterward, the bridge defers probe when IOMMU is not ready.
> This causes the bridge to be moved to the end of the dpm list when
> deferred probe kicks in. The order of the dpm list for bridge and
> endpoint is reversed.
> 
> Add reordering code to move the bridge and its children and consumers to
> the end of the pm list so the order for suspend and resume is not altered.
> The code also move device and its children and consumers to the tail of
> device_kset list if it is registered.
> 
> Signed-off-by: Feng Kan <fkan at apm.com>
> Signed-off-by: Toan Le <toanle at apm.com>
> ---
>  V3:
> 	1. additional code comment changes
>  V2:
>         1. change patch title from "move device and its children..."
>         2. move define based on Bjorn's comment
>         3. rename function name and comment content
> 
>  drivers/base/base.h |  3 +++
>  drivers/base/core.c | 20 ++++++++++++++++++++
>  drivers/base/dd.c   |  4 +---
>  3 files changed, 24 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/base/base.h b/drivers/base/base.h
> index d800de6..a75c302 100644
> --- a/drivers/base/base.h
> +++ b/drivers/base/base.h
> @@ -161,3 +161,6 @@ static inline void module_remove_driver(struct device_driver *drv) { }
>  extern void device_links_no_driver(struct device *dev);
>  extern bool device_links_busy(struct device *dev);
>  extern void device_links_unbind_consumers(struct device *dev);
> +
> +/* device pm support */
> +void device_pm_move_to_tail(struct device *dev);
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 110230d..3b37906 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -148,6 +148,26 @@ static int device_reorder_to_tail(struct device *dev, void *not_used)
>  }
>  
>  /**
> + * device_pm_move_to_tail - Move set of devices to the end of device lists
> + * @dev: current device pointer

What does "current" mean here, exactly?

I guess it would be better to say "Device to move" or similar here.

> + *
> + * This is a device_reorder_to_tail() wrapper taking the requisite locks.
> + *
> + * It moves the device along with all of its children and all of its consumers

"The device" is @dev, so it's better to use @dev here, like

"It moves @dev along with ..."

Thanks,
Rafael