HowTo: Undervolt your notebook CPU for longer battery life

[aldeby]

Of course, but something went wrong last time.
I'm not suggesting you to always delete them, just once to try fixing the problem you are experiencing.

[M4rotku]

I tried deleting those files and running it again. Once again, it ran the first time and then the second time I received the same error.

[aldeby]

As far as I remember in phc_tweaked_vids VIDs on the right cannot be higher than those on the left: i.e. 40 34 23 15 is OK while 0 34 23 15 will probably prompt the reported error. Values in phc_tweaked_vids are related to the number listed in phc_cur_pos

phc_cur_pos should list number 0 or 1 since you only have two power states.
It should be 0 if your CPU crashed while running the script the first time.

you can use the vids listed in phc_tweaked_vids after the CPU crashes by adding a few extra values to ensure stability.

if the scripts goes down to 0 most of the times there are some problems.
in my case, for example, it manages to go down to 0 for the first FID, however the second lower one crashes at 35. I cannot set phc 0 35 -- -- because this will prompt an error. First value should definitely be equal of higher.

Hope to remember well...

[M4rotku]

My value on the left went down to 0 and then the script quit after it got to a negative one. But the value on the right stayed at 19 the whole time. I assumed that it was supposed to do that.

But the script didn't crash the system yet, so it still needs to run a few more times.

How would I go about fixing this?

[Tao]

There is a new version of PHC (0.3.1) (two days ago). http://sourceforge.net/project/showf...roup_id=161063

Some changes, longer documentation and a patch for 2.6.26rc8 kernel.

[M4rotku]

Tao,

that looks promising. However, I have no idea as to which thing I need off of that site. If I am using 2.6.24-19-generic as my kernel and an Intel Core2 Duo CPU, then which package would I want to download and use? Also, would I still be following this guide or would I have to use a new set of instructions?

Much thanks,
M4rotku

[Sebastral]

Tao,

that looks promising. However, I have no idea as to which thing I need off of that site. If I am using 2.6.24-19-generic as my kernel and an Intel Core2 Duo CPU, then which package would I want to download and use? Also, would I still be following this guide or would I have to use a new set of instructions?

Much thanks,
M4rotku

- find out if you use acpi_cpufreq with lsmod | grep cpufreq

- if you do follow these instructions to enable phc;

http://ubuntuforums.org/showpost.php...0&postcount=54

- install phctool from the link that looked promising to you.

- do sudo modprobe msr to enable the analasys feature

- find out the lowest possible vid for your cpu with the relevant steps in this howto

- set the new vids using the relevant steps in this howto

Hope this helps. Ever since I couldn't get the vids lower then the lowest official vid I gave up on this. but I've upgraded to kernel 2.6.24 and gave it a shot again. if I can believe phctool and powertop it seriously appears lower vids than the lowest standard vid is possible (using 2.6.24-19 and phc 0.3.1)

[M4rotku]

- if you do follow these instructions to enable phc;

http://ubuntuforums.org/showpost.php...0&postcount=54

- install phctool from the link that looked promising to you.

Those instructions were for the 18 kernel, will they work with the 19?

[Sebastral]

Those instructions were for the 18 kernel, will they work with the 19?

Positive, I have done it myself.

[M4rotku]

Tao,

How do I install that patch, it wasn't a .deb package and I don't have any idea how to use it? When I tried to use the install script, it tried to go through wine so it might be a windows app.