PCI interrupt allocation question..

[Julian Elischer]

On Wed, 14 Jan 2004, Stijn Hoop wrote:

> On Tue, Jan 13, 2004 at 03:26:00PM -0800, Julian Elischer wrote:
> > The kernel includes teh ichsmb driver to try access the SMBus 
> > for temperature reading reasons (yes I know I can do it other ways..)
> > 
> > Any thoughts that move me towards getting th eichsmb driver working on
> > this machine are welcome.
> 
> Make sure that the mainboard really does support SMBus -- it turns out that
> this is optional. The ICH docs talk about a bit that should be enabled in the
> PCI config when SMB is present. I ran into this once, it should be documented
> in the archives (of -current off the top of my head). OTOH, I didn't even
> succeed in getting an ichsmb device probed so this might be something totally
> unrelated.
> 
> FWIW, I had to try other ways to get the temperature (xmbmon & related). I
> don't have the box anymore or I'd show you the exact config...

xmbmon uses the SMBus to read the temperatures but it does it from
userland using direct read and write operations
and when there are timing glitches caused by the process not getting
scheduled quite quick enough you get garbage results..
teh theory is that the kernel driver wouldn't be susceptible to this
but it looks like unless I resort to polling I will not be able to use
it because it relies on the interrupts and they are not being delivered.

ASUS motherboards actually turn off the SMBus. (why?)
So you need to turn it back on before you can read the temperatures..
I have a little script that uses pciconf to do it..

> 
> --Stijn
> 
> -- 
> Beware of he who would deny you access to information. For in his heart
> he thinks himself your master.
> 		-- Sid Meier, "Sid Meier's Alpha Centauri"
>