RE: ACPI C4 support

Grover, Andrew
2004-03-01T19:03:57Z

> [mailto:acpi-devel-admin-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org] On Behalf Of
> Stefan Behlert
> > No. pblk_length is 0 or 6. Not 5 nor 7 ;)
>
> Sorry, I don't understand: We've a Laptop with a DSDT with
> Processor (\_PR.CPU0, 0x01, 0x00001010, 0x07)
> in it.
> Comment from the responsible BIOS-team:
> "Our processor block object is 7 bytes in length because we
> also support
> C4 (P_LVL4) which is at <P_BLK>+6. Therefore, the
> size/length must be
> reported as 7 and not 6."
>
> Is the '7' the BIOS-developer mentioned the same '7' as
> mentioned by you?

This is wrong.

There is confusion here because what older systems do on C3 is different
from what more recent systems do on C3, at the electrical level. I know
at least internally the improved C3-like state was called "C4" but to
the OS it just looks just like C3, and the value for C4 should go in
P_LVL3. P_BLK length should remain 6.

The only way to get more than C1, C2, and C3 is via the _CST object.

Please tell the BIOS developer this. I have an old BIOS developers guide
version that agrees with them but I just asked the experts internally
and they said no.

Thanks -- Regards -- Andy

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