Re: [PATCH] nvme: hwmon: Add support for throttling temperature feature

[Tokunori Ikegami <ikegami.t@gmail.com>]

On 2022/08/07 15:05, Guenter Roeck wrote:
> On Sat, Aug 06, 2022 at 08:58:49PM +0900, Tokunori Ikegami wrote:
>> Note: Sorry let me resend the mail below as text format since it was not
>> delivered to the mailing lists as contained HTML subpart.
>>
>> Hi,
>>
>> Thanks for your comments.
>>
>> On 2022/08/06 17:31, Guenter Roeck wrote:
>>> On Sat, Aug 06, 2022 at 02:46:06PM +0900, Tokunori Ikegami wrote:
>>>> NVMe drives support host controlled thermal management feature as optional.
>>>> The thermal management temperature are different from the temperature threshold.
>>>> So add functionality to set the throttling temperature values.
>>>>
>>>> Signed-off-by: Tokunori Ikegami <ikegami.t@gmail.com>
>> I think actually the suggested attributes are not met with the throttling
>> temperatures as below.
>>
>>    temp[1-*]_emergency: Temperature emergency max value, for chips supporting
>> more than two upper temperature limits.
>>    temp[1-*]_lcrit: Temperature critical min value, typically lower than
>> corresponding temp_min values.
>>
>>    Thermal Management Temperature 1 (TMT1): This field specifies the
>> temperature, in Kelvins, when the controller begins to transition to lower
>> power active power states or performs vendor specific thermal management
>> actions while minimizing the impact on performance (e.g., light throttling)
>> in order to attempt to reduce the Composite Temperature.
>>    Thermal Management Temperature 2 (TMT2): This field specifies the
>> temperature, in Kelvins, when the controller begins to transition to lower
>> power active power states or perform vendor specific thermal management
>> actions regardless of the impact on performance (e.g., heavy throttling) in
>> order to attempt to reduce the Composite Temperature.
>>
> That happens a lot. That is neither a reason nor an argument to introducing
> new attributes to match chip descriptions. If we would do that, we would end
> up with lots and lots of different and unmanageable attributes.
>
> Please note that the functionality is associated with thermal management,
> so you might want to discuss your attributes with the thermal subsystem
> maintainers.

Okay I see and have understood as it is difficult to use hwmon 
attributes for the thermal management functionality.

Regards,
Ikegami

>
> Guenter