[LinuxBIOS] Geode GX1/5530: How to forward SMI to a regular IRQ

Juergen Beisert juergen127 at kreuzholzen.de
Tue Aug 8 08:47:46 CEST 2006

Hi Ronald,

On Monday 07 August 2006 22:48, Ronald G Minnich wrote:
> > On Monday 07 August 2006 11:19, myself wrote:
> >>I try to write a native sound driver for the Geode GX1/5530a Companion
> >>chip. Problem here: The sound chip only generates SMI. Does anyone knows
> >> a trick or a chipset switch that let me forward this SMI to a regular
> >> IRQ? Its too ugly to use a polling loop.... ;-)
> >
> > Sorry. I think I must explain: I'm using linuxbios on this Geode system,
> > so there is no SMM emulation of the sound hardware. Thats why I'm
> > searching for a solution to forward the SMI to a regular IRQ. Has someone
> > experience in programming this SMM code? Maybe a short routine that only
> > triggers a regular interrupt when an SMI occures would help.
> Is there some reason to continue to use SMI? why not just drive the
> hardware directly w/o smi?

Yes, there is: The audio hardware part of the chip can only generate SMI. I 
didn't find any chipset settings to let it generate a regular IRQ instead. 
There is only one register to let the SMM software trigger a regular IRQ.

On Monday 07 August 2006 23:27, Ronald G Minnich wrote:
> we may need to write a stupid trampoline to get from smi to linux.

What does it mean? A small SMM rotuine? That would be great. Can I help to 
write it?


More information about the coreboot mailing list