CPU frequency scaling problem - laptop users, please check this

[NoOp]

On 05/24/2011 11:17 AM, A. Kromic wrote:
> On 05/24/2011 07:34 PM, NoOp wrote:
...
>> You mention in your bug report "works perfectly with kernels up to
>> 2.6.32-24". But your last post: "Still not working with latest release
>> kernels: 2.6.32-32 (Lucid)". So I'm confused - with which kernel *is*
>> cpu scaling currently working on your machine?
>>
>>
> What I meant is this: my system's CPU scaling has worked and still works
> perfectly with all old kernels up to 2.6.32-24, with any kernel newer
> than that it doesn't work at all. I can reproduce it anytime, either
> chosing a kernel from GRUB, or by booting a live CD. Another fact
> perhaps worth noting is that it doesn't matter if it is a 32- or 64-bit
> Ubuntu - I've checked with both, and again the problem depends just on
> the kernel version.
> 
> I don't quite get what the problem is, it seems it's quite rare. However
> so far, I couldn't find anything else but the kernel to blame, per the
> above mentioned fact. No amount of tinkering with other software (like
> acpi, cpu frequency managers etc.) not hardware (battery, BIOS options)
> showed any difference at all...
...
There were issues in earlier kernels on archlinux as well. Might be of
interest (read both pages):
<https://bbs.archlinux.org/viewtopic.php?id=46195>
In that posting Thomas Renninger did a patch:
cpufreq acpi: only call _PPC after cpufreq ACPI init funcs got called
already
So perhaps something like that has raised it's head again in the newer
kernels.

You might want to have a look at:
https://wiki.ubuntu.com/Kernel/FAQ
https://wiki.ubuntu.com/Kernel/Debugging
to see if there are tools etc., there can can be of help in figuring out
the issue. Also ask on #ubuntu-kernel IRC channel on FreeNode & the
kernel mailing list to see if someone there can offer further suggestions.

Good luck as I suspect this may be a tough one to figure out.