CPU C4 vs. C3 states, BIOS support and 1.5W power savings

[Török Edvin]

On 6/21/07, Florian Reitmeir <florian at reitmeir.org> wrote:
>
> it shows me max C3 in 2.6.21 , and 2.6.20 show me max. C4.

2.6.20 is not tickless IIRC, so C4 won't have a big impact.

If you had C4 in 2.6.20, but not in 2.6.21 I suggest to open a
bugreport on bugzilla.kernel.org.

Perhaps use acpidump to dump the _CST tables. It is a bit complicated
how to do that, you need to dump the SSDT, disassemble with iasl,
locate the CST physical address, and length, dump again from that
address, and decompile again.

Are you using same BIOS with 2.6.21 vs. 2.6.20?

--Edwin