Arch Linux

rbrownclown

Member

Registered: 2006-12-29

Posts: 125

cpufreq - Need Help

I'm following the instructions in the Beginners Guide.  I'm stuck at the section about configuring cpufreq.

Here's what I've done so far:

1.  I installed cpufrequtils with pacman.  Simple enough.

2.  Edited rc.conf and added cpufreq to the daemon section.  I put it in between the "()" right next to the title (there were other daemon names there).

3.  Edited /etc/conf.d/cpufreq and changed the governor line to governor="conservative"

4.  I'm not sure about the exact speed of my processor (pathetic thing is - I should know, just built the thing last month).  All I know is that it's an AMD Athlon 64.  Windows XP claims it's only 2 GHz.  I took a guess and put 2GHz next to min_freq and 2.5GHz next to max_freq.

5.  The next step, I'm not sure I understand.  Here's what it says in the guide:

Add the frequency scaling modules to your /etc/rc.conf modules line (e.g. speedstep_centrino for Pentium M processors or powernow-k8 for the Athlon 64).

I edited /etc/rc.conf and added powernow-k8 in the "()" next to the title.  This is what confuses me.  There was nothing in the "()" before I added that module.  Am I putting this in the correct place?  Also, I didn't install the 64 bit kernel (would prefer a 32 bit system right now).  Does that mean I have to use a different module?  If so, which one?

6.  It then told me to modprobe the powernow-k8 module.  It gave me errors.  So stupidly, I figured that if I restart the system, it will start automatically since I added it to rc.conf.  I restarted, and now I can't boot because of a kernel panic.

I need to be pointed in the right direction here.  :?

bones

Member

From: Brisbane

Registered: 2006-03-24

Posts: 322

Website

Re: cpufreq - Need Help

Let's start from the beginning. What were the errors you got when you when you did modprobe? We may be able to work out the problem from that

---

"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."

lucke

Member

From: Poland

Registered: 2004-11-30

Posts: 4,018

Re: cpufreq - Need Help

I, noone else (well, maybe apart from some scallywag, yarr), but I shall come to your aid!

I haven't done it that way, but I think you should set MIN_FREQ to 800Mhz and MAX_FREQ to 2GHz.

You should add powernow-k8 to MODULES array in /etc/rc.conf - if you have MOD_AUTOLOAD set to yes (which turns on module autoloading), your MODULES array is probably indeed empty.

It could be that you can't load powernow-k8 because you don't have C'n'Q (Cool'n'Quiet) enabled in BIOS (modprobe should say something about device not available).

Alas, I'm utterly clueless as to the reason for the panic (changes made by you shouldn't have any impact). And that's the thing that bothers you the most at the moment, obviously. If you were more verbose about this kernel panic, maybe I would be able to assist further.

rbrownclown

Member

Registered: 2006-12-29

Posts: 125

Re: cpufreq - Need Help

Alas, I'm utterly clueless as to the reason for the panic (changes made by you shouldn't have any impact). And that's the thing that bothers you the most at the moment, obviously. If you were more verbose about this kernel panic, maybe I would be able to assist further.

Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

lucke

Member

From: Poland

Registered: 2004-11-30

Posts: 4,018

Re: cpufreq - Need Help

Are you using GRUB?

You might try changing the initrd line to point to "kernel26-fallback.img" (with GRUB you can do it "interactively", without booting into the system) and try booting.

rbrownclown

Member

Registered: 2006-12-29

Posts: 125

Re: cpufreq - Need Help

Are you using GRUB?

You might try changing the initrd line to point to "kernel26-fallback.img" (with GRUB you can do it "interactively", without booting into the system) and try booting.

How do I do that?  I hit C at the menu, and it took me to a command line.  The Grub config is /boot/grub/menu.ls, correct?  I tried editing it through nano, and I got an error.

lucke

Member

From: Poland

Registered: 2004-11-30

Posts: 4,018

Re: cpufreq - Need Help

Press "E".

rbrownclown

Member

Registered: 2006-12-29

Posts: 125

Re: cpufreq - Need Help

Cool.  It boots now.  I can't quote it word for word (flashed by too fast), but it said something about not being able to find powernow-k8 at boot.  Is it possible that I don't even have this module on my system?  I just did the modprobe and the error is:

-bash: syntax error near unexpected token "new line"

rbrownclown

Member

Registered: 2006-12-29

Posts: 125

Re: cpufreq - Need Help

I just thought of something.  Could it be that I'm installing this in a virtual machine?  I looked in it's "bios" and power management is disabled, but maybe it just doesn't work in this environment.  I wanted to get this working once before I did it for real, but I guess I can't if this is the case.  *prints beginners guide*

Edit - Well... I installed it for real.  Having the exact same problem.  Ugh.

lucke

Member

From: Poland

Registered: 2004-11-30

Posts: 4,018

Re: cpufreq - Need Help

You mentioned something about Windows. Did you get it to work there (you have to install AMD Driver, set Power Management to Minimal, then you can check your cpu speed on main tab of System Control Pane)?

What is the actual error that modprobe prints?

rbrownclown

Member

Registered: 2006-12-29

Posts: 125

Re: cpufreq - Need Help

What is the actual error that modprobe prints?

-bash: syntax error near unexpected token "new line"

lucke

Member

From: Poland

Registered: 2004-11-30

Posts: 4,018

Re: cpufreq - Need Help

Ah, that one. That's strange. Maybe you should try "modprobe powernow_k8".

rbrownclown

Member

Registered: 2006-12-29

Posts: 125

Re: cpufreq - Need Help

Ah, that one. That's strange. Maybe you should try "modprobe powernow_k8".

It recognized that and spit out yet another error.

FATAL: Error inserting powernow_k8 (lib/modules/2.6.19-ARCH/kernel/arch/i386/kernel/cpu/cpufreq/powernow_k8.ko): No such device

I also tried powernow-k8.  That didn't work either.

http://wiki.archlinux.org/index.php/PowerNow

The link above was pretty useful.  I typed dmesg | grep powernow and got something different then what they said meant it was supported.  I'll post the results if needed, but it's an annoyingly long type.

lucke

Member

From: Poland

Registered: 2004-11-30

Posts: 4,018

Re: cpufreq - Need Help

Are you completely sure that you have C'n'Q enabled in BIOS? As said earlier, such error appears when C'n'Q isn't enabled.

As noted before, you might check whether it works in XP, if feasible.

-edit-

Why type, not copy?

rbrownclown

Member

Registered: 2006-12-29

Posts: 125

Re: cpufreq - Need Help

I shortened the results because they just repeat the same thing once or twice.

powernow-k8: Found 1 AMD Athlon(tm) 64 Processor 3000+ processors (version 2.00.00)
powernow-k8: BIOS error - no PSB or ACPI _PSS objects

I fooled around a little in the bios and enabled power management.  Does the same thing.

lucke

Member

From: Poland

Registered: 2004-11-30

Posts: 4,018

Re: cpufreq - Need Help

Symptoms are as if C'n'Q weren't enabled.

Things that come to my mind:

- you may be missing the setting in BIOS, it should be somewhere in CPU configuration (at least that's where it is in my case);
- there might be an update for your BIOS available;
- your motherboard (less likely, if at all, CPU) doesn't support C'n'Q;
- something's borked with linux kernel itself.

rbrownclown

Member

Registered: 2006-12-29

Posts: 125

Re: cpufreq - Need Help

Hmm... well... I'll fool around and see if I can find anything.  Will it say CnQ specifically in the bios, or will I have to edit options that replace it?  I didn't see it last time I looked, I'll look more carefully again.

In the meantime, is this really necessary?  I have a desktop with a lot of case fans, so temperature isn't a big deal.  Does Ubuntu have this enabled by default (that's what I'm coming over from)?

lucke

Member

From: Poland

Registered: 2004-11-30

Posts: 4,018

Re: cpufreq - Need Help

It _should_ be called "Cool and Quiet' or similar.

By no means is that compulsory. It's nice to have even on a desktop, however, for a few reasons:

- CPU uses less electrical energy - which has impact on your bills and environment;
- CPU runs cooler - if you have thermally controlled fans, they will be less noisy; lowering temperature increases CPU longevity (well, it probably won't be used _that_ long anyway).

ploxiln

Member

Registered: 2006-10-27

Posts: 50

Re: cpufreq - Need Help

I just thought of something.  Could it be that I'm installing this in a virtual machine?

Yes. Because the windows kernel is the primary controller of the cpu, it has to do the powernow stuff. Linux doesn't have direct control since it's really running via a vmware module in the windows kernel which gives just-about-native speed (but which can't give hardware control of the cpu).