Re: [lm-sensors] [PATCH] hwmon: (coretemp) Fix TjMax for Atom N450/D410/D510 CPUs

Yong Wang
2010-01-18T08:33:15Z

On Mon, Jan 18, 2010 at 09:14:51AM +0100, Jean Delvare wrote:
> On Mon, 18 Jan 2010 14:58:21 +0800, Yong Wang wrote:
> > On Sun, Jan 17, 2010 at 09:05:36PM +0100, Jean Delvare wrote:
> > > That's where I am confused. The patch checks for the presence of the
> > > Intel NM10, which, reading its description looks much like a south
> > > bridge and not a memory controller (north bridge). So I think the patch
> > > is wrong (or at least incomplete).
> >
> > Sorry, I made a mistake in the patch description. The new Atom CPU is
> > coupled with integrated gfx and memory controller in one package. NM10
> > chipset is another chip. This patch does check the presence of the
> > integrated memory controller, i.e. 00:00.0 Host bridge device, which
> > will always be present no matter whether NM10 chipset is used or not.
>
> OK. Then indeed the patch description was rather bad. Even the comments
> in the code are misleading, they mention the NM10 when they don't
> really have to.
>
> But at least if the code itself is OK... that's not that bad.
>
> > > Anyway, how difficult would it be to set TjMax based on the CPUID? I
> > > presume that the Intel Atom 400 and 500 series have their own CPUID
> > > value, haven't they? This would seem even easier that checking for a
> > > PCI device.
> >
> > CPUID value (family and model number) remains the same for all Atom CPUs
> > thus far. That is why we check the new Atom CPU this way.
>
> What about the stepping value? Don't these CPU models have their own?
>

The stepping value is not architectually defined. Therefore, it is not
the recommended way to detect CPU make and models.

Thanks
-Yong