Cpu Scaling Linux MInt Gloria 7

[/hack]

I would like to kindly ask anyone to explain me about CPU Scaling and how should I enable it in my hp 2133. I'm currently using Linux Mint 7. Will the acpi_osi=”!Windows 2006” add at the kernel boot line be enough to have it set? Thanks beforehand.

[mikez]

Depends on the kernel version you are running. So what version? (I.E: output of: uname -a)
Q2: Why do you think it isn't working?
- - - -
The system (should) be maintaining stats on the scaling - - exactly what depends on version/build.
Find the path to the cpufreq directory:
cd /sys
find . -name 'cpufreq'
cd to the full path returned by the above command (if not found, then you don't have it loaded) -
browse around in that directory and its sub-directories - just 'cat' any files found.
- - - -
The man(ual) command is your friend - each of the above commands is explained, for instance:
man cat

[/hack]

Ok then, I got the Kernel version line by running uname -a:

Linux chibi-san 2.6.28-11-generic #42-Ubuntu SMP Fri Apr 17 01:57:59 UTC 2009

Besides that, I tried the find command like this:

find -name 'cpufreq'

and nothing came out of it.

I did a "locate 'cpufreq'" and I found a lot of paths.

/etc/laptop-mode/conf.d/cpufreq.conf

/lib/modules/2.6.28-11-generic/kernel/arch/x86/kernel/cpu/cpufreq/e_powersaver.ko

/lib/modules/2.6.28-11-generic/kernel/arch/x86/kernel/cpu/cpufreq/p4-clockmod.ko

are some examples of the most significative (i guess...) the other ones being just about the gnome applet.

Thanks for your help.

[PsynoKhi0]

Mint 7 is based on Ubuntu Jaunty (9.04) so the same settings apply, add e_powersaver to your /etc/modules files, see mikez post:
http://www.hp2133guide.com/forums/vi...b45a19831ff4cc

[mikez]

There may have been some changes since then - -
There is a kernel patch that allows the acpi frequency control driver to load and work;
That patch may or may not be in the kernel you are running, distributions decide when to introduce a patch on their own schedule.
- - - -
Best way to tell, is to just try it -
The acpi_cpufreq module is the preferred one to use - it **should** auto-load.
- - - -
You can tell which one loaded by listing the loaded modules:
lsmod
or
sudo lsmod
after opening a terminal window.
- - - -
You can tell if it is working by checking the cpufreq/stats under the directory
tree rooted at /sys -
Enter:
find /sys -name cpufreq
to get the full pathname to that directory; and there should be a 'stats' sub-directory.
Any of the files can be read by entering:
cat put_filename_here
- - - -
If the 'find' command above does not find a cpufreq directory - none of the cpufreq drivers are loaded.
= = = =
If your distribution kernel does not (yet) support acpi_cpufreq for the VIA processor -
Then, and only then, try using the e_powersaver driver;
but if you have a 1.6Ghz machine - keep an eye on the cpu temperatures;
it is possible on the 1.6Ghz machines that e_powersaver will try to run the
processor outside of the recommended freq/voltage curve.

Note: The acpi_cpufreq driver uses the same freq/voltage tables in the BIOS
that MS-Windows does. So that means it is the better tested driver.

[PsynoKhi0]

The acpi_cpufreq driver uses the same freq/voltage tables in the BIOS
that MS-Windows does. So that means it is the better tested driver.

Erm so you're referring to this? http://patchwork.kernel.org/patch/28609/
Dang, so much for e_powersaver on this forum...
Thanks for the info still (would be even better if you could remember to drop a line here as soon as you find out about this kind of stuff, not everyone reads kernel patch mailing lists :lol: )

[mikez]

I thought that I made about 600 posts on the subject this Spring/Summer:
http://forum.netbookuser.com/viewforum.php?id=8
With build announcements included here.
This forum only got announcements because the builds I posted did not have the Broadcom Wifi driver included.

- - - -

Yeah, you got the background discussion - H. W. did *not* get back with a fix for e_powersaver;
To fix it correctly, VIA Tech. would have to reveal how to read the VRM output pins in the MSRs and they aren't talking.
The C7-M technical reference is less than helpful - it has errors in the printed tables;
I did do a spreadsheet workup of the errata and send it to the person in charge of that publication at VIA;
But the control bit mapping table in the silicon for the 1.6Ghz processor remains documented as "undocumented".

Previous to that discussion, is the patch to acpi_cpufreq - use L. T.'s version.
The best of the builds (both single frequency and variable frequency) are still posted as above.
Each post includes the patches and configuration applied to the kernel source.

I think I had about three people from this list try the builds and comment;
Wanna be number 4?

[/hack]

sorry mikez, no acpi_cpufreq module showed up when I did the lsmod. I guess its not loading, would you please help me have it?

[mikez]

The goal is simple, the path can be a bit confusing. . .

Goal: Get acpi_cpufreq to load before the Ubuntu scripting can load e_powersaver.

Since I don't have the slightest idea about what kernel you have -
All I can give are general instructions -
I am assuming here that the distribution installs initramfs-tools.

You will have to be user "root" (the administrator) to make these changes -
so either bring up a "superuser terminal" or a regular terminal and if working
in a regular terminal, log in as "root" (su -l) or precede commands with sudo.

*) Edit your /etc/initramfs-tools/modules file to include acpi_cpufreq, like:

# List of modules that you want to include in your initramfs.
#
# Syntax:  module_name [args ...]
#
# You must run update-initramfs(8) to effect this change.
#
# Examples:
#
# e_powersaver

acpi_cpufreq

# whatever else you need loaded early.

Since I don't know what kernel name you are booting, update the initrd image for all of them:

update-initramfs -u -k all

That should take care of getting acpi_cpufreq loaded before e_powersaver - -
Presuming of course that your distro kernel has the driver patched to load for VIA.

Another "VIA processor" thing - include in your kernel command line: "idle=halt" (without the quotes of course).
This shuts off the code which uses the mwait instruction (c7-m doesn't do mwait).

Edit the boot menu stanza that you will be using in the /boot/grub/menu.lst file, similar to:

title           Linux-2.6.30 - kernel 2.6.30-ce1200v-09200
root            (hd0,0)
kernel          /boot/vmlinuz-2.6.30-ce1200v-09200 root=/dev/sda1 resume=/dev/sda2 ro quiet splash idle=halt
initrd          /boot/initrd.img-2.6.30-ce1200v-09200
quiet

Of course, your kernel and initrd names will be different - but that is where the command option goes on the 'kernel' line of the stanza.

After rebooting - you can check which driver has control:

root@cb01:~# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
acpi-cpufreq

And you should see the results of it at work:

root@cb01:~# cat /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state
1200000 68569
1000000 1575
800000 1096
600000 1165
400000 100323

Note that the report does not include the time in "halt" (0.000Ghz core clock).

[mikez]

I just downloaded the default Mint-7/Gloria CD -
it is running the Ubuntu, kernel version: 2.6.28-11-generic

Translation: If that is what you are running (uname -a) - abandon all hope of using acpi_cpufreg.

The "Live Image" version does not even have acpi_cpufreq built, let alone built correctly for VIA.
Your going to need something much more recent - try one of the recent Ubuntu/Karmic kernels - 2.6.32.something if they have one.