public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Bill Davidsen <davidsen@tmr.com>
To: David Wilson <mcs6502@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: What is the best way to identify a new x86 processor that does not implement the CPUID instruction?
Date: Wed, 06 Aug 2008 08:12:10 -0400	[thread overview]
Message-ID: <4899951A.1040704@tmr.com> (raw)
In-Reply-To: <3666888f0808050008h38e11737k8e6cb9c4c85aa457@mail.gmail.com>

David Wilson wrote:
> I recently bought a Norhtec MicroClient JrSX which uses the Vortex86sx
> System on Chip processor (see http://vortex86sx.com/ for more
> details). This is identified as a Cyrix 486SLC by the Linux kernel due
> to the lack of a CPUID instruction. While this may be seen as a
> cosmetic defect, if the kernel can identify the processor correctly it
> could, for example, use the clock divisor code provided by the
> manufacturer to slow down and speed up the CPU when required.
> 
> The question is: how to differentiate this chip from the Cyrix part?
> The freely available "brief data sheet" does not provide much detail.
> 
> I have thought of a couple of schemes but am not really keen on either:
> 
> 1) Clock speed - the SoC runs at 300+ MHz while the Cyrix part is < 100 MHz
> 2) Look at the PCI VID/PID for the north bridge as this is part of the CPU die.
> 
> Does anyone have any suggestions? Thanks.

Your (2) sounds reasonable.

-- 
Bill Davidsen <davidsen@tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot

  parent reply	other threads:[~2008-08-06 12:02 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-05  7:08 What is the best way to identify a new x86 processor that does not implement the CPUID instruction? David Wilson
2008-08-05  9:26 ` David Newall
2008-08-06  2:33 ` Jike Song
2008-08-06 12:12 ` Bill Davidsen [this message]
2008-08-08 11:00 ` Andi Kleen

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=4899951A.1040704@tmr.com \
    --to=davidsen@tmr.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mcs6502@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox