PECI temperature in lm-sensors

[Аладышев Константин]

Does someone have any experience with enabling PECI monitoring on nuvoton
SuperIOs ?

I'm trying to enable it on board with Haswell+Lynxpoint CPU and  NCT6776
SuperIO.

But all I see in lm-sensors output for now is zero temperature for PECI
Agent.

Does coreboot have any SuperIO chips/Intel CPUs/motherboards, that have this
functional enabled? What is usually need to be done to enable PECI
monitoring?

[Pierre P]

Hi,

Had a similar issue on a KCMA-D8. When running sensors-detect you have to force probing of i2c chips (default choice is "NO" if you just press enter when asked) then hopefully with one of them it will detect other sensors.

Hope this helps

Pierre

________________________________
From: coreboot  on behalf of Аладышев Константин 
Sent: Monday, January 23, 2017 3:17 PM
To: [e-mail]
Subject: [coreboot] PECI temperature in lm-sensors

Does someone have any experience with enabling PECI monitoring on nuvoton
SuperIOs ?

I'm trying to enable it on board with Haswell+Lynxpoint CPU and  NCT6776
SuperIO.

But all I see in lm-sensors output for now is zero temperature for PECI
Agent.

Does coreboot have any SuperIO chips/Intel CPUs/motherboards, that have this
functional enabled? What is usually need to be done to enable PECI
monitoring?

[Nico Huber]

On 23.01.2017 15:17, Аладышев Константин wrote:
> Does someone have any experience with enabling PECI monitoring on nuvoton
> SuperIOs ?
>
> I'm trying to enable it on board with Haswell+Lynxpoint CPU and  NCT6776
> SuperIO.
>
> But all I see in lm-sensors output for now is zero temperature for PECI
> Agent.

I'd first make sure, that the PECI interface is actually connected to a
PECI slave. Do you have evidence that this is the case? It's not unusual
to leave it unconnected.
> Does coreboot have any SuperIO chips/Intel CPUs/motherboards, that have this
> functional enabled? What is usually need to be done to enable PECI
> monitoring?

FWIW (cf. superio/ite/it8772f and others), you have to program the PECI
slave address and the command used to retrieve the temperature readings.
What to program seems to be documented in a secret PECI specification (I
could only find a license agreement, WTF?). How to program it, is super
i/o specific (see datasheet of your chip).

I wonder though, what are you up to? You only need PECI if you want your
super i/o to to something automatically (like fan control) based on the
readings. If you only want to read out the temperature, you can also
directly ask the processor (MSR 0x19c, IIRC).

Nico

[Аладышев Константин]

1) Yes, PECI pin in SuperIO is actually configured as PECI pin and is connected to PECI pin on Haswell CPU
2) I don't have secret PECI docs either, so I don't know what else should I do...
3) You're right, I want to configure SuperIO to control fans on motherboard based on CPU temperature.

-----Original Message-----
From: Nico Huber [mailto:[e-mail]] 
Sent: Monday, January 23, 2017 11:42 PM
To: Аладышев Константин
Cc: [e-mail]
Subject: Re: [coreboot] PECI temperature in lm-sensors

On 23.01.2017 15:17, Аладышев Константин wrote:
> Does someone have any experience with enabling PECI monitoring on 
> nuvoton SuperIOs ?
>
> I'm trying to enable it on board with Haswell+Lynxpoint CPU and  
> NCT6776 SuperIO.
>
> But all I see in lm-sensors output for now is zero temperature for 
> PECI Agent.

I'd first make sure, that the PECI interface is actually connected to a PECI slave. Do you have evidence that this is the case? It's not unusual to leave it unconnected.
> Does coreboot have any SuperIO chips/Intel CPUs/motherboards, that 
> have this functional enabled? What is usually need to be done to 
> enable PECI monitoring?

FWIW (cf. superio/ite/it8772f and others), you have to program the PECI slave address and the command used to retrieve the temperature readings.
What to program seems to be documented in a secret PECI specification (I could only find a license agreement, WTF?). How to program it, is super i/o specific (see datasheet of your chip).

I wonder though, what are you up to? You only need PECI if you want your super i/o to to something automatically (like fan control) based on the readings. If you only want to read out the temperature, you can also directly ask the processor (MSR 0x19c, IIRC).

Nico

[Felix Held]

Hi!
> I don't have secret PECI docs either, so I don't know what else should I do...

Maybe the three peci.c files in 3rdparty/chromeec can help you. At least 
those contain the meaning of some of the magic values.
> You're right, I want to configure SuperIO to control fans on motherboard based on CPU temperature.

Haven't looked at the details, but version 1.2 of the nct6776 datasheet 
(can be found on the internet) seems to have the description of the 
relevant registers.

Regards
Felix