linux-kernel - Re: [PATCH] ACPI: PPTT: Inform user that table offset used for Physical processor node ID

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Message-ID: <0244dcc3-6006-2a67-e861-d2bcce4360f6@huawei.com>
Date:   Thu, 2 Apr 2020 15:51:44 +0100
From:   John Garry <john.garry@...wei.com>
To:     Jeremy Linton <jeremy.linton@....com>, <rjw@...ysocki.net>,
        <lenb@...nel.org>
CC:     <linux-acpi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <sudeep.holla@....com>, <linuxarm@...wei.com>,
        <wanghuiqiang@...wei.com>
Subject: Re: [PATCH] ACPI: PPTT: Inform user that table offset used for
 Physical processor node ID

On 02/04/2020 14:55, Jeremy Linton wrote:
> Hi,
> 
> On 4/2/20 7:22 AM, John Garry wrote:
>> If the the Processor ID valid is not set for a Physical Processor Package
>> node, then the node table offset is used as a substitute. As such, we
>> may get info like this from sysfs:
>>
>> root@(none)$ pwd
>> /sys/devices/system/cpu/cpu0/topology
>> root@(none)$ more physical_package_id
>> 56
>>
>> Inform the user of this in the bootlog, as it is much less than ideal, 
>> and
>> they can remedy this in their FW.
>>
>> This topic was originally discussed in:
>> https://lore.kernel.org/linux-acpi/c325cfe2-7dbf-e341-7f0f-081b6545e890@huawei.com/T/#m0ec18637d8586f832084a8a6af22580e6174669a 
>>
>>
>> Signed-off-by: John Garry <john.garry@...wei.com>
>>
>> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
>> index 4ae93350b70d..b4ed3c818e00 100644
>> --- a/drivers/acpi/pptt.c
>> +++ b/drivers/acpi/pptt.c
>> @@ -515,6 +515,8 @@ static int topology_get_acpi_cpu_tag(struct 
>> acpi_table_header *table,
>>           if (level == 0 ||
>>               cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_ID_VALID)
>>               return cpu_node->acpi_processor_id;
>> +        if (level == PPTT_ABORT_PACKAGE)
>> +            pr_notice_once("Physical package node Processor ID valid 
>> not set, will use table offset as substitute\n");

Hi Jeremy,

> 
> What happens in the find_acpi_cpu_topology_hetro_id() case, if the last 
> IDENTICAL node isn't a socket/etc. Are we expecting to warn of a missing 
> processor container there as well?

ok, I could just use this then:

if (flags & ACPI_PPTT_PHYSCIAL_PACKAGE)
	pr_notice_once("Physical package node Processor ID ...")

As I recall, this tag for hetro id is not exposed to userspace (yet).

Thanks,
John