Re: [RFC] [PATCH] cpufreq: allow full selection of default governors

Dave Jones
2007-04-25T00:04:10Z

On Tue, Apr 24, 2007 at 03:05:36PM -0700, Nish Aravamudan wrote:
> On 4/24/07, Dave Jones <davej@redhat.com> wrote:
> > On Tue, Apr 24, 2007 at 09:03:23PM +0000, William Heimbigner wrote:
> > > The following patches should allow selection of conservative, powersave, and
> > > ondemand in the kernel configuration.
> >
> > This has been rejected several times already.
> > Ondemand and conservative isn't a viable governor for all cpufreq
> > implementations (ie, ones with high switching latencies).
>
> This piques my curiosity -- some governors don't work with some
> cpufreq implementations. Are those implementations in the kernel or in
> userspace? If in the kernel, then perhaps there should be some
> dependency expressed there in Kconfig between cpufreq implementation
> and the available governors

it can't be solved that easily. powernow-k8 for example is fine to
use with ondemand on newer systems, where the latency is low.
On older models however, it isn't.

> > Also, see the
> > comment in the Kconfig a few lines above where you are adding this.
>
> Are these governors unfixable? If

tbh, I've forgotten the original issues that caused the comment
to be placed there. Dominik ?

> Just looking for more info -- feel free to just point me at the archives.

cpufreq-list archives are at http://lists.linux.org.uk/mailman/listinfo/cpufreq
(though only available to list members)

Dave

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