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

["Lucero Palau, Alejandro" <alejandro.lucero-palau@amd.com>]

On 01/10/2026 21:31, Dave Jiang wrote:
>
> 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?


I would say you can not use a device as supplier before device_add() 
happens for such a supplier, and if it does happen after device_del(), 
something is wrong with the caller.


Your suggestion is likely making the code more legible, but it does not 
change the functionality I added. Does it? Not saying it would not help, 
but I can not understand your comment for suggesting it which seems to 
point to potential problems I did not see.


> 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;
>        }