Re: Centrino question

Len Brown
2004-05-23T03:20:09Z

On Fri, 2004-05-21 at 14:48, Martin Hermanowski wrote:
> On Fri, May 21, 2004 at 10:38:57AM -0700, Ow Mun Heng wrote:
> > On Fri, 2004-05-21 at 04:52, Karol Kozimor wrote:
> > > Thus wrote Cyril Wattebled:
> > > > However, I don't understand, I was told that the centrino processor and chipset
> > > > supports C3 and even C4.
> >
> > C3 is Supported
> >
> >
> > active state: C2
> > default state: C1
> > bus master activity: ffffffff
> > states:
> > C1: promotion[C2] demotion[--] latency[000] usage[01028830]
> > *C2: promotion[C3] demotion[C1] latency[050] usage[04785987]
> > C3: promotion[--] demotion[C2] latency[050] usage[00001327]
> >
> > This is a Dell D600 1.4g. c3 values are low because I have the USB mouse
> > on right now. (note the fffffff??)
>
> The same here (ibm t41p, 1.7GHz). Using USB forces c2. But c1 seems to be used
> very seldom (usage count of 10).

Known issue with C1 and C2...
When C2 has very low latency, say 1, then after we're in C1
10 times and promote to C2, we never demote to C1 again, ever.

The processor driver is tracking how successful we are at
being idle, but is not tracking how non-idle the system is,
so our current demotion policy is somewhat simplistic.

-Len