# CPU Frequency Scaling - laptop without a battery?



## joeyabrams (May 19, 2014)

I have a laptop powered via the A/C Adapter, I have no battery. The problem I'm having is that the CPU frequency is locked in at the minimum frequency (800MHz) regardless of the load on the system. From my understanding this is due to not having a battery installed. Is there a way around this to make the system scale the frequency as it should?

As it is now the only way to get my system to run at its maximum frequency or any frequency above the minimum 800MHz is by manually setting the variable dev.cpu.0.freq to the desired frequency. I ran Linux on this system before trying FreeBSD and I was able to pass the following parameter to my boot loader via GRUB's configuration: 
	
	



```
processor.ignore_ppc=1
```
 which stopped the CPU from being locked into the lowest frequency.

Is something like this possible with FreeBSD, or is that even advisable?

Thanks.


----------



## emmex (May 19, 2014)

I have just removed the battery from my laptop and it works as expected: the CPU frequency ranges form 1.40 GHz to 2.50 GHz. I have set my CPU following the guide in the FreeBSD wiki TuningPowerConsumption.

Hope these help.
Maurizio


----------

