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SubjectRe: [PATCH][2.6.7-mm1] perfctr ppc32 update
Benjamin Herrenschmidt writes:
> On Tue, 2004-06-22 at 15:09, Mikael Pettersson wrote:
> > Benjamin Herrenschmidt writes:
> > > Hrm... your code will not work with externally clocked timebases
> > > (like the G5) and I'm not sure you get the core freq. right with
> > > CPU that can do clock slewing or machines that can switch the
> > > core/bus ratio (laptops).
> >
> > Do you mean the PLL_CFG code that's been in -mm for the last couple
> > of weeks, or just the recently posted update? The update replaced
> > in-kernel /proc/cpuinfo parsing (gross) with OF queries taken straight
> > from the pmac code in arch/ppc/platform/.
> >
> > I'm ignoring 970/G5 until IBM releases the damn documentation.
>
> Well, the G5 can have it's own tb but can also be externally clocked and
> that's how Apple does. I'm not sure about all G4 models.

So what you're saying is that PLL_CFG may not reflect the true
relationship between the TB frequency and the core frequency?

That shouldn't be a problem as long as there's _some_ in-kernel
interface for finding that out. If querying OF isn't the correct
approach, then what is?

/Mikael
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