Re: [PATCH v2 2/3] ACPI / PPTT: fix build when CONFIG_ACPI_PPTT is not enabled

["Rafael J. Wysocki" <rafael@kernel.org>]

On Tue, Jun 5, 2018 at 6:18 PM, Sudeep Holla <sudeep.holla@arm.com> wrote:
>
>
> On 05/06/18 17:12, Rafael J. Wysocki wrote:
>> On Tue, Jun 5, 2018 at 5:33 PM, Sudeep Holla <sudeep.holla@arm.com> wrote:
>>>
>>>
>>> On 05/06/18 16:00, Rafael J. Wysocki wrote:
>>>> On Tue, Jun 5, 2018 at 4:35 PM, Sudeep Holla <sudeep.holla@arm.com> wrote:
>>>>> Though CONFIG_ACPI_PPTT is selected by platforms and nor user visible,
>>>>> it may be useful to support the build with CONFIG_ACPI_PPTT disabled.
>>>>>
>>>>> This patch adds the missing dummy/boiler plate implementation to fix
>>>>> the build.
>>>>>
>>>>> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
>>>>> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
>>>>> ---
>>>>>  include/linux/acpi.h      | 15 +++++++++++++++
>>>>>  include/linux/cacheinfo.h |  2 +-
>>>>>  2 files changed, 16 insertions(+), 1 deletion(-)
>>>>>
>>>>> Hi Rafael,
>>>>>
>>>>> If you are fine with this, can you provide Ack, so that we route this
>>>>> through ARM64 tree where most of the ACPI PPTT support is present.
>>>>>
>>>>> Regards,
>>>>> Sudeep
>>>>>
>>>>> v1->v2:
>>>>>         - removed duplicate definition for acpi_find_last_cache_level
>>>>>
>>>>> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
>>>>> index 8f2cdb0eca71..4b35a66383f9 100644
>>>>> --- a/include/linux/acpi.h
>>>>> +++ b/include/linux/acpi.h
>>>>> @@ -1299,8 +1299,23 @@ static inline int lpit_read_residency_count_address(u64 *address)
>>>>>  }
>>>>>  #endif
>>>>>
>>>>> +#ifdef CONFIG_ACPI_PPTT
>>>>>  int find_acpi_cpu_topology(unsigned int cpu, int level);
>>>>>  int find_acpi_cpu_topology_package(unsigned int cpu);
>>>>>  int find_acpi_cpu_cache_topology(unsigned int cpu, int level);
>>>>> +#else
>>>>> +static inline int find_acpi_cpu_topology(unsigned int cpu, int level)
>>>>> +{
>>>>> +       return -EINVAL;
>>>>
>>>> Why -EINVAL?
>>>>
>>>
>>> I am not sure either. I used to return -ENOTSUPP, but IIRC someone
>>> suggested to use it only for syscalls. Also I just based it on other
>>> existing functions in acpi.h
>>>
>>> I am open for any alternatives if you think that is better here.
>>
>> It would be good to make it consistent with the error codes returned
>> by the functions when they are present.
>>
>> Anyway, it's fine by me if that's consistent with the other acpi.h stubs.
>>
>
> Thanks, indeed I copied it from existing stubs.
>
> Can I take this as official Ack ?

Yes, please.