New cpufreq framework and drivers
Bruno Ducrot
ducrot at poupinou.org
Wed Feb 2 12:38:32 PST 2005
On Wed, Feb 02, 2005 at 12:03:47PM -0800, Nate Lawson wrote:
> Colin Percival wrote:
> >Nate Lawson wrote:
> >
> >>Hardware drivers are of two types, absolute
> >>and relative. SpeedStep, Powernow, etc. are absolute drivers in that
> >>they set the cpu's base frequency. ACPI throttling, Longrun, etc. are
> >>relative drivers that reduce the processor's clock to a fraction of
> >>its current base (i.e., they have an additive effect.)
> >
> >
> >If my first glance at the patch is correct, this would have my laptop (a
> >1.4GHz
> >Pentium M) reporting the availability of the frequencies 600MHz, 800MHz,
> >etc.
> >from enhanced speedstep, along with the frequencies 300MHz, 400MHz,
> >500MHz, and
> >700MHz obtained via 50% clock throttling.
>
> That is correct. The code to support relative drivers was removed
> before posting to give the basic framework more testing before I commit
> it shortly. The relative support will go in soon after that code is
> committed.
>
But longrun is relative though and can scale voltage.
(And the point that longrun can control frequency itself is imho irrelevant).
--
Bruno Ducrot
-- Which is worse: ignorance or apathy?
-- Don't know. Don't care.
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