Re: [PATCH v2 1/4] driver core: Check for supplier requiring PM at link creation

[Dave Jiang <dave.jiang@intel.com>]

On 10/1/26 6:20 AM, alucerop@amd.com wrote:
> From: Alejandro Lucero <alucerop@amd.com>
> 
> PM initialization could not be necessary for some devices.
> 
> Avoid checking for supplier PM initialization if so.
> 
> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
> ---
>  drivers/base/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 4c0c373998a1..bf0513beafad 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -840,7 +840,7 @@ struct device_link *device_link_add(struct device *consumer,
>  	 * SYNC_STATE_ONLY link, we don't check for reverse dependencies
>  	 * because it only affects sync_state() callbacks.
>  	 */
> -	if (!device_pm_initialized(supplier)
> +	if ((!device_pm_not_required(supplier) && !device_pm_initialized(supplier))
>  	    || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
>  		  device_is_dependent(consumer, supplier))) {
>  		link = NULL;

A no PM supplier can now be linked at any point: before device_add(), while it fails, or after device_del(). Maybe replace with a helper like this?

static bool device_link_supplier_ready(struct device *supplier)
{
      /* no PM devices never enter dpm_list, so check registration directly */
      if (device_pm_not_required(supplier))
              return device_is_registered(supplier);

      return device_pm_initialized(supplier);
}

...

      if (!device_link_supplier_ready(supplier) ||
          (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&
           device_is_dependent(consumer, supplier))) {
              link = NULL;
              goto out;
      }