# some questions about ACPI, I2C and SMBus



## schetchik (Oct 15, 2009)

Hi.
I have a computer with motherboard Intel D845HV and FreeBSD 6.4-RELEASE on it.
I want see cpu temperature and fan speed, but i has some troubles with it.

Why there are not acpi.thermal in my "sysctl -a" output?
I try use mbmon, but it output is like this

```
$ mbmon

Temp.=  0.0,  0.0,  0.0; Rot.=    0,    0,    0
Vcore = 0.00, 0.00; Volt. = 0.00, 0.00,  0.00,   0.00,  0.00
```
lmmon -i output is

```
Motherboard Temp               Voltages

 255C / 491F / 528K        Vcore1:   +3.984V
                           Vcore2:   +3.984V
    Fan Speeds             + 3.3V:   +3.984V
                           + 5.0V:   +6.654V
    1:    0 rpm            +12.0V:  +15.938V
    2:    0 rpm            -12.0V:  -15.938V
    3:    0 rpm            - 5.0V:   -6.654V
```

What difference between I2C and SMBus, and how define what is using on my motherboard? and what drivers i need to install?

What i need to do? pls help


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## SirDice (Oct 15, 2009)

schetchik said:
			
		

> [*]What difference between I2C and SMBus,



See smbus(4):



> *DESCRIPTION*
> The smbus system provides a uniform, modular and architecture-independent system for the implementation of drivers to control various SMB devices and to utilize different SMB controllers (I2C, PIIX4, Brooktree848, vm86...).
> 
> *System Management Bus*
> The System Management Bus is a two-wire interface through which simple power-related chips can communicate with rest of the system. It uses I2C as its backbone (see iicbus(4)).



Also see http://en.wikipedia.org/wiki/I²C


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## mickey (Oct 15, 2009)

schetchik said:
			
		

> Why there are not acpi.thermal in my "sysctl -a" output?



Probably because the developers of this M/B's ACPI code were too lazy, to define the corresponding thermal zones within it's ACPI DSDT 

You have made sure, that you are running the latest available BIOS version, haven't you?


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## schetchik (Oct 15, 2009)

dmidecode:

```
BIOS Information
        Vendor: Intel Corp.
        Version: HV84510A.86A.0018.P04.0107302001
        Release Date: 07/30/2001
```

too old 
thanks
will try fresh BIOS


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