Dell Latitude Laptop Processor Stuck at 800MHz

At home I use a Dell Latitude laptop which I found discarded. I’ve been using Xbuntu on it for over a year. It has been OK. It’s nothing blazing fast or great, but it works for doing some basic side development.

Recently, I noticed that my CPUFreq-indicator was never moving off the lowest level. I tried changing the CPU governor to performance but nothing changed. I ran cpufreq-info and got this message:

current policy: frequency should be within 800 MHz and 800 MHz. The
governor "performance" may decide which speed to use within this range.

Crap!

How To Fix

I tried Googling around for all types of search terms related to this. I found some people attributing it to version 340 of the NVidia drivers and other saying it was a problem with the machine going into hibernate. I finally came on this post: Dell Laptop Stuck at 800MHz – Linux Fix. FINALLY!

The short of it is you’ll need to add some kernel options to GRUB to have the kernel ignore the suggestions from Dell’s BIOS.

You’re going to need to edit /etc/default/grub. Look for the line which starts with GRUB_CMDLINE_LINUX_DEFAULT. You’re going to want to append to it this kernel option which will tell it to ignore the suggestions from the BIOS: processor.ignore_ppc=1. As an example, here is what I have in my GRUB file:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash processor.ignore_ppc=1"

After you edit /etc/default/grub you’ll need to update the actual grub.conf file. You can easily do this by running the command sudo update-grub.

If you don’t have any errors you can go ahead and reboot your laptop. Now if you run cpufreq-info you should see the full range of frequencies supported in the current policy message.

Again, I would really like to thank the author of this post: Dell Laptop Stuck at 800MHz – Linux Fix! Without this I’d still be stuck in slow land!

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I'm a software engineer. Look into the about page for more information about me.
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