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From: "H. Peter Anvin" <hpa@zytor.com>
To: Dave Jones <davej@suse.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: 2.5.x: arch/i386/kernel/cpu
Date: Tue, 18 Jun 2002 21:43:19 -0700	[thread overview]
Message-ID: <3D100BE7.4040802@zytor.com> (raw)
In-Reply-To: 20020619063807.B25509@suse.de

Dave Jones wrote:
> On Tue, Jun 18, 2002 at 08:45:18PM -0700, H. Peter Anvin wrote:
>  > Whomever broke up arch/i386/kernel/setup.c and created the CPU
>  > directory (very good idea) messed up in at least one place:
> 
> Patrick Mochel takes credit/glory/fame/blame for this one.

Note that this is great.  We should do the same with bugs.h which is, if 
anything, an even worse mess.

>  > The *AMD-defined* CPUID flags (0x80000001) are not just used on AMD
>  > processors!  In fact, at least AMD, Transmeta, Cyrix and VIA all use
>  > them; I don't know about Centaur or Rise.  Intel supports the actual
>  > level starting with the P4 although it returns all zero.
> 
> Bugger, you're right.

Looked a little harder, and it should *definitely* be moved to generic, 
since it also includes the CPU name string check, which is supported 
even on Intel P4 CPUs.

> On my Cyrix III box before..
> 
>  CPU: After vendor init, caps: 00803135 80803035 00000000 00000000
>  CPU:     After generic, caps: 00803135 80803035 00000000 00000000
>  CPU:             Common caps: 00803135 80803035 00000000 00000000
> 
> and after..
> 
>  CPU: After vendor init, caps: 00803135 80000000 00000000 00000000
>  CPU:     After generic, caps: 00803135 80000000 00000000 00000000
>  CPU:             Common caps: 00803135 80000000 00000000 00000000
> 
> Interesting how it's picking up that 8 in the 2nd set of caps, but
> not any of the other bits..

That's the 3DNow! bit... I was thinking it might be handled specially, 
but it looks like that's only done for Centaur chips.  Are you sure your 
CPU isn't being mis-identified as Centaur by the new code?

>  > It should, in my opinion, be moved into generic_identify().  Anyone
>  > who has a reason why that shouldn't be done speak now or I'll send the
>  > patch to Linus.
> 
> Sounds reasonable to me, unless Patrick has a preferred way of fixing 
> this problem.
> 
>         Dave
> 
> 



  reply	other threads:[~2002-06-19  4:43 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-06-19  3:45 2.5.x: arch/i386/kernel/cpu H. Peter Anvin
2002-06-19  4:38 ` Dave Jones
2002-06-19  4:43   ` H. Peter Anvin [this message]
2002-06-19  4:58     ` Dave Jones
2002-06-19  5:03       ` H. Peter Anvin
2002-06-21 18:18 ` Patrick Mochel

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