Re: [ACPI] [PATCH] ACPI/Processor: C1/C3 states promotion and demotion

[Bruno D. <du...@po...>]

On Wed, Feb 11, 2004 at 07:37:16PM +0800, Yu, Luming wrote:
> 
> > On Wed, Feb 11, 2004 at 10:19:22AM +0800, Yu, Luming wrote:
> > > > > Some processors seems to support only C1 and C3 states, for 
> > > > instance... mine ;-)
> > > > > (Pentium III Coppermine). The problem is that, in this 
> > > > case, no promotion or
> > > > > demotion are linking those two states, therefore the 
> > > > preocessor never goes to C3!
> > > > > 
> > > > 
> > > > There is no intel-like processors for which there is C3, but 
> > > > no C2.  So
> > > > you have actually to fake a C2 (which should be at a latency 
> > > > of 30 IIRC).
> > > > 
> > > 
> > > I'm not sure a faking C2 can work as expected, because
> > > C2 power state is an optional ACPI clock state that needs 
> > > chipset hardware support. (ACPI spec 2.0b  8.1.3)
> > > 
> > 
> > We are talking about a PIII Coppermine that need to be put in sleep
> > mode (C2) before deep sleep (C3).
> 
> According to ACPI spec, entering  C2 needs chipset hardware support.
> So it is possible that only C1 and C3 get supported, despite CPU 
> can support C1 , C2, and C3. 
> 

I am not aware of southbridge that are buggy in order to enter a PIII
coppermine in the sleep state whereas it can can put it in deep sleep
state.  Hmm, well, appart perhaps earlyer version of the ich2m ?
I don't remember.  Will check.

-- 
Bruno Ducrot

--  Which is worse:  ignorance or apathy?
--  Don't know.  Don't care.