On Wed, Jun 10, 2009 at 04:10:59PM +0200, Jan Stary wrote:
> On Jun 10 12:09:26, Joachim Schipper wrote:
> > On Wed, Jun 10, 2009 at 11:53:39AM +0200, Jan Stary wrote:
> > > Scenario: 4.5 on MSI Wind PC, everything works. I use this machine
> > > because it is relatively low-power and quiet.
> > >
> > > The fan rotation changes with how much the CPU is used
> > > (could someone translate this into the real thing please?),
> > > without me doing anything about it on the OS level.
> > >
> > > Unless I run something heavy, such as launching mozilla, the fan keeps
> > > pretty quiet (below the level of noise that would annoy me), but still,
> > > it could be quiter. Is there a way to control the fan RPM from the OS?
> > > (Unsurprisingly, hw.sensors.adt0.fan0 is readonly.)
> >
> > This is not an answer to your query, but are you sure that turning off
> > the cooling for the CPU is a good idea? It does turn on for a reason...
>
> I don't want to turn it off. I want to lower the rotation speed a bit.
>
> > You may want to investigate hw.setperf, which may be used to put the CPU
> > in a low-power (and -performance) state. Try sysctl hw.setperf=0 (the
> > lowest possible state).
>
> I never tried hw.setperf=0; but with hw.setperf=90, then 80, then 70,
> the fan actually starts to rotate _faster_ (thus becoming noisier).
Are you sure? Typically, hw.setperf=90 does nothing (correlate it with
hw.cpuspeed, which gives the actual CPU speed).
Joachim
