[ltp] C4 after powertop-update

[shadowkernel]

Hi,
If you have not notice big difference of power dissipation, I think it 
is unnecessary to fix this. "If it isn't broken, don't fix it!"

Arno Trautmann wrote:
> Hi Guys!
>
> You often helped me to better understand my machine, and I am very 
> thankful for this… so now I have again a question that is for 
> understanding, and not a problem… so everything works fine, but I want 
> to know why…
>
> X61s, Arch Linux
> Yesterday I upgradet my system (pacman -Syu) and downloaded a new 
> powertop-version. When I start it, I get the output
>
> Your CPU supports the following C-states : C1 C2 C3 C4
> Your BIOS reports the following C-states : C1 C2 C3
>
> which has never been there before. And just now I am really confused: 
> yesterday it showed me for the BIOS C1 C2 C4… and in powertop itself 
> it showed me that the CPU was in C4—I was really happy about this ;)
> powertop says:
>
> Cn                Avg residency       P-states (frequencies)
> C0 (cpu running)        ( 4.2%)         1.61 Ghz     0.0%
> polling           0.0ms ( 0.0%)         1.60 Ghz     0.0%
> C1                0.0ms ( 0.0%)         1200 Mhz     0.0%
> C2                0.0ms ( 0.0%)          800 Mhz   100.0%
> C3                3.3ms (95.8%)
>
> ok, this is nearly what I am used to. Yesterday, there was C4 instead 
> of C3… but new is ”polling“—what does that mean? And before the 
> upgrade, the first and second P-state had the same frequency. Why is 
> there now a difference of 10MHz?…
>
> But now really the question: How can I get into C4 again? Do I have to 
> check my BIOS for this? Why did I have C4 yesterday but not now?…
>
> Hope, you can help me or give me some hints where I can get good 
> information about this behaviour.
>
> Thanks,
> Arno