No C states on powertop = no power reduction ?

[Arjan van de Ven]

Frédéric BOITEUX wrote:
> 	Hello,
> 
>   I'm using powertop on my laptop since a long time and it helped me
> a lot to expand its old battery's life. I also use a desktop which has
> also a mobile processor (Pentium M) and tried recently to run powertop
> on this computer : powertop doesn't show any C-States information
> (P-states are here). I've looked a bit the DSDT table, and nothing is
> defined inside for the processor.
>   I'm wondering if it's useful to try to lower number of
> wake-ups/second (i.e. if it can lower consupmtion / temperature of the
> CPU) or if it's useless as ACPI don't define low power C -states ?
>   And is there any hope to extend the ACPI DSDT table to add them,
> knowing it's an old model no more supported by vendors ?
> 

being more idle, even without C-states, does help. At least to a point; the deeper the C-states you
have the more it's important to be idle longer.

Adding C-states, while not impossible, isn't all that easy either ..... especially on older systems
(on newer ones it's relatively easy because hte interface got standardized)