Re: i2c and indirect vs. direct config

[Paul Goyette <paul%whooppee.com@localhost>]

On Sun, 3 Jun 2018, Rhialto wrote:

> On Sun 03 Jun 2018 at 05:07:34 +0800, Paul Goyette wrote:
> > Please note that the X99 chip-set actually has two different SMBus
> > controllers!
> >
> > There's the "minimal-functionality" controller that sits on the "system
> > management PCI bus" and driven by the imc/imcsmb driver.  But there is also
> > a "full-function" SMbus at "pci0 dev 31 function 3" which uses the ichsmb
> > driver.  It is the former device via which my spdmem and sdtemp devices are
> > accessed.
>
> But do those two controllers access two different buses, or do they
> access the same bus?
>
> If the latter, the better controller can be used...

Different busses.  In fact, there are a total of FIVE i2c busses on this 
machine:

	mainbus
           |
	   + -- pci0 (pci bus 0)
	   |      |
	   |      +-- ichsmb0 (dev 31 func 3)
	   |             |
	   |             +-- iic0
	   + -- pci6 (pci bus 255)
	   |      |
	   |      +-- imc0 (dev 19 func 0)
	   |             |
	   |             +-- iic1
	   |             +-- iic2
	   + -- pci6 (pci bus 255)
	          |
	          +-- imc1 (dev 22 func 0)
	                 |
	                 +-- iic3
	                 +-- iic4

All i2c busses are separate and unique.


> -Olaf.
> --
> ___ Olaf 'Rhialto' Seibert  -- Wayland: Those who don't understand X
> \X/ rhialto/at/falu.nl      -- are condemned to reinvent it. Poorly.

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