Re: v2.6.26-rc7: Negative powertop values

[Arjan van de Ven <arjan@linux.intel.com>]

Pavel Machek wrote:
> On Tue 2008-07-08 06:52:51, Arjan van de Ven wrote:
>> On Sun, 6 Jul 2008 21:48:45 +0200
>> Pavel Machek <pavel@suse.cz> wrote:
>>
>>>> [I assume you know that doing a software unplug you burn more power
>>>> than by leaving the cpu idle]
>>> We should really fix that one day...
>> yeah but it's incredibly hard to get right (in the light of the bios
>> constantly changing what our allowed C-states are)... and the best case
> 
> What can happen there? So BIOS decides C4 may no longer be cool idea
> because we have AC power now, but that does not mean C4 stops working,
> right?

it's also the other way around; you put the sleepy core in C4 because C6 is not available;
then C6 becomes available and the sleepy core is wasting power;

Either way, the *best* case you get is to be equal to being idle.....