Re: [PATCH 1/4] ACPI/APMT: Use stable device ID

[Ilkka Koskinen <ilkka@os.amperecomputing.com>]

On Thu, 9 Jul 2026, Robin Murphy wrote:
> On 09/07/2026 3:39 pm, Robin Murphy wrote:
>> The APMT node format includes a unique identifier, so we can use this as
>> the platform device ID to give userspace stable and identifiable device
>> names, rather than auto numbering dependent on how the table is parsed.

That's a good idea.

>> 
>> Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
>> Cc: Hanjun Guo <guohanjun@huawei.com>
>> Cc: Sudeep Holla <sudeep.holla@kernel.org>
>> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
>> ---
>>   drivers/acpi/arm64/apmt.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/acpi/arm64/apmt.c b/drivers/acpi/arm64/apmt.c
>> index bb010f6164e5..ba48fcb26d52 100644
>> --- a/drivers/acpi/arm64/apmt.c
>> +++ b/drivers/acpi/arm64/apmt.c
>> @@ -79,7 +79,7 @@ static int __init apmt_add_platform_device(struct 
>> acpi_apmt_node *node,
>>   	int ret, count;
>>   	struct resource res[DEV_MAX_RESOURCE_COUNT];
>>   -	pdev = platform_device_alloc(DEV_NAME, PLATFORM_DEVID_AUTO);
>> +	pdev = platform_device_alloc(DEV_NAME, node->id);
>
> Per the Sashiko comment, while I really wouldn't expect it to be an issue in 
> practice, I guess we could explicitly check and truncate node->id to INT_MAX 
> (probably with some degree of warning) here just in case.

Yeah, it probably and hopefully won't happen but it makes sense to have a 
warning message regardless. With it

Reviewed-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>

Cheers, Ilkka

>
> Cheers,
> Robin.
>
>>   	if (!pdev)
>>   		return -ENOMEM;
>> 
>
>