Re: About p4-clockmod breakage/removal

Len Brown
2008-05-14T03:35:53Z

On Tuesday 13 May 2008, Matthew Garrett wrote:
> On Tue, May 13, 2008 at 08:48:00PM -0400, Len Brown wrote:
>
> > Assuming this is a laptop with a batter,
> > I'd certainly be interested if you could run BLTK
> > and measure any benefit to p4-clockmod (I've never
> > been able to)
>
> The most plausible benefit to p4-clockmod is its utility in throttling
> the CPU if it would otherwise cause the system to overheat. From that
> point of view, I think it's worth keeping around - especially since not
> all machines expose T states via ACPI.

Matthew,
I'm delighted in your efforts to make Linux better, I really am.
So I'm sorry that for the 3rd message in a row I have to
completely disagree with you.

cpufreq is not designed to manage thermals, and putting p4_clockmod
underneath it to manage thermals is a mistake.

There is already a well known thermal throttling interface
available via ACPI and it does not need p4_clockmod to run.
Passive trip points work automatically even without cpufreq being present.
If they do not, then we need to fix them.

p4-clockmod should have been removed from the tree over a year ago.

-Len