Re: managing a fan speed via memory address

good morning Adrian,

1. I am just learning :) Not 100% sure ACPI has anything to do with fan
control ( still it looks that it actually does )
-- found the Advanced Configuration and Power Interface Specification PDF.
Will spend some time grasping the ideas
2. to quickly write any driver I will have to first find out how to do it
:) any guidance ( preferable in textual form will be greatly appreciated )
will learn it :)
3. there isn't a single thermal sensor, but the SAS disks report their
temperatures
( via dmidecode if I am not mistaken, or some other program -- I will be
more sure tomorrow morning ).
so, theoretically I could be able to read their temperature and decide if I
would like to send more power to the fan.

On Wed, May 3, 2023 at 2:14 AM Adrian Chadd <adrian@freebsd.org> wrote:

> Is it not an ACPI driver? If not, you could write a quick fan driver!
>
> Is there a thermal sensor(s) you could read to see how warm they get?
>
>
>
> -adrian
>
>
> On Tue, 2 May 2023 at 17:06, Dmitry N. Medvedev <dmitry.medvedev@gmail.com>
> wrote:
>
>> good morning,
>>
>> Recently I have learned about the dmidecode program and found the address
>> of the FRNTFAN port in my HP Z420 machine: 0x0037.
>> Since I am a complete newbie, I would like to learn if there is a way to
>> read and change the value at this address.
>> I need a bit of guidance.
>>
>> *The context*: I have added 8 SAS disks to the machine, put noctua fan
>> in front of them and connected the fan to the FRNTFAN port on the
>> motherboard.
>> It looks like the fan works, but I am sure the disks would benefit if the
>> fan produced more pressure. Which I fantasize I could do via changing the
>> value at the said address.
>> Not sure, of course.
>>
>> best regards,
>> Dmitry N. Medvedev
>>
>