Linux PHC for Ubuntu 10.10 Maverick Meerkat

Today I have officially published the PHC kernel for Ubuntu 10.10 Maverick Meerkat. The Linux PHC project provides cpufreq kernel modules for undervolting Intel and AMD processors on a Linux platforms. This gives you the ability to save energy, lower the CPU temperature and expand battery time.

Linux PHC usually doesn't need a custom kernel, as it only provides some additional kernel modules, which can be compiled out-of-tree. Unfortunately the Ubuntu kernel is that much optimized for fast booting so the default cpufreq kernel modules like acpi-cpufreq (used for Intel processors) and powernow-k8 (used for AMD processors) are compiled-in and can't be replaced by other kernel modules like Linux PHC ones. To workaround this problem I started to build special -phc kernels, which are prepared for use with Linux PHC. Strictly speaking they contain cpufreq modules like acpi-cpufreq and powernow-k8 in module form instead of compiled-in. Moreover to make it easier to install and receive updates for -phc kernels we provide a PPA on Launchpad.

If you want to know more about Linux PHC take a look at the Linux PHC forum and the PHC wiki. The installation notes for the PHC kernel are in this thread.

Comments on this Article

  • Alex says:

    Awesome!! I installed Maverick on my thinkpad and have been painfully aware of how badly it overheats without this kind of control.

  • gregor says:

    Thanks for your precious work, reducing power consumption and saving our ears !
    I recently upgraded to Maverick (10.10) and there seems to be no compatible offtree release for the 2.6.35 kernel available at What can I do ?

  • Peter Sasi says:

    I have been using the phc kernels for 10.04 and now upgraded to 10.10. since then I do not see the controls in /sys/devices/system/cpu/cpu0/cpufreq/ what module should I look for in lsmod?
    I badly need this, since otherwise my TPad shuts down during some x264 transcoding… 🙁

    • David says:

      Hi Peter,
      You should first check, if the PPA is still activated. As far as I know Ubuntu disables all third-party repositories during upgrade.
      Next you have to check if you are really running a PHC kernel. You could use uname -r to get the running kernel version. PHC kernel versions are ending with -phc.
      Then you should check lsmod. If you are running phc-k8, then search for phc_k8. I don’t know for phc-intel as I only own AMD systems. Nevertheless if you are using phc-intel you have to recompile it manually on each kernel update because phc-intel doesn’t use DKMS.

      • pumpkin says:

        Sorry to hijack this …

        I’m running 2.6.35-23-generic-phc on a fresh 10.10 install and “lsmod | grep phc” show nothing at all.



        • David says:

          Please take a look at the installation notes post:

          Actually the interesting part for you should be:

          The Maverick kernels do NOT include the PHC modules. It is only prepared for PHC, so you have to install the appropriate PHC modules yourself. This should be very easy with the offtree releases. (See Releases thread)

          • Peter Sasi says:

            The cuplprit was exactly the missing phc module. You have to keep reinstalling, hogy 2.6.35-23, -24 (updates to the same kernel version) and so on. That is a job that could be obviously be done with dkms.

            Any clue why it does not work that way?

          • David says:

            It works that way with phc-k8, but phc-intel doesn’t use DKMS.
            This is because they are maintained differently by different developers.
            phc-k8 is maintained as separate kernel module, which tries to be compatible to as much kernel versions as possible.
            phc-intel is maintained as patch upon acpi-cpufreq, which most time needs to be adjusted for each kernel version.

  • Dima says:

    David, do you plan to release a PHC kernel for Ubuntu 11.04?

    • David says:

      I don’t use Natty myself because of the power consumption bug.
      Nevertheless I am planing to release a PHC kernel for Natty, but it will delay a bit. I hope I can get it ready this weekend, but I can’t guarantee it.

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