Date: Wed, 8 Apr 2009 20:24:57 +0200
From: Robert Schwebel <r.schwebel@pengutronix.de>
To: Michael Riepe <michael.riepe@googlemail.com>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
       tglx@linutronix.de
Subject: Re: Identifying Intel Atom Z500PT
Message-ID: <20090408182457.GX5367@pengutronix.de>
References: <20090407222144.GU5367@pengutronix.de> <49DCE2E3.7050700@googlemail.com>
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Hi Michael,

On Wed, Apr 08, 2009 at 07:46:11PM +0200, Michael Riepe wrote:
> Robert Schwebel wrote:
> > Does anyone have an idea how to properly identify an Atom Z500PT cpu?
> > The get_model_name() mechanics in arch/x86/kernel/cpu/common.c uses
> > cpuid() to find out about the brand id, which is "Genuine Intel(R) CPU"
> > with family 6 and model 28.
>
> Family 6, model 28, stepping 2 seems to be common to all current Atoms
> -- my 330 reports the same. There are some flags, however, that
> currently only appear in the Z series, e.g. vmx is not available on the
> 230/330/N270. To differentiate between the latter, you could look for
> 64-bit support (which is missing in the N270) and the number of cores.
> Besides that, the 230/330 models lack the speedstep feature.
>
> I don't know if there's a way to distinguish a -P model from a -PT
> model. But from a software point of view, they should be identical anyway.

Yup, should not matter from the software side.

> > Below is the output of /proc/cpuinfo on that box:
> >
> > root@phyCORE:~ cat /proc/cpuinfo | grep model | head -n 2
> > model           : 28
> > model name      : Genuine Intel(R) CPU        @ 1.10GHz
>
> Strange - the 330 reports:
>
> model name      : Intel(R) Atom(TM) CPU  330   @ 1.60GHz
>
> (running 2.6.29).

Looks like the model name string comes from the BIOS, I suppose I'll
have to talk to the BIOS guys in order to resolve that issue.

rsc
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