From owner-freebsd-bugs Fri Apr 18 13:49:13 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id NAA02316 for bugs-outgoing; Fri, 18 Apr 1997 13:49:13 -0700 (PDT) Received: from isbalham.ist.co.uk (isbalham.ist.co.uk [192.31.26.1]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id NAA02309 for ; Fri, 18 Apr 1997 13:49:06 -0700 (PDT) Received: from gid.co.uk (uucp@localhost) by isbalham.ist.co.uk (8.8.4/8.8.4) with UUCP id VAA24322; Fri, 18 Apr 1997 21:44:39 +0100 (BST) Received: from [194.32.164.2] by seagoon.gid.co.uk; Fri, 18 Apr 1997 21:39:23 +0100 X-Sender: rb@194.32.164.1 Message-Id: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 18 Apr 1997 21:36:54 +0100 To: KATO Takenori From: Bob Bishop Subject: Re: kern/3292: Cyrix 486 performance problem Cc: freebsd-bugs@freefall.freebsd.org Sender: owner-bugs@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk At 3:04 +0100 18/4/97, KATO Takenori wrote: >To determine cache disable/enable by default is to determine support >all/not-all Cx486 box. If CPU cache is enabled by default, FreeBSD >cannot boot on old Cyrix-unaware motherboards. > >Because Cyrix sold 486SLC/DLC series as `up-grade products'[etc] ^^^^^^^ Aha. I just noticed. I'm not talking about SLC/DLC here, I'm talking DX2. SLC/DLC have device ID in the range 0x00 to 0x03 for OEM parts, 0x04 to 0x07 for retail upgrades. DX2 has ID 0x1b. I would say it's unlikely that a DX2 will be found on a motherboard that doesn't support it. [Apologies for sending the above twice, accidentally hit send while I was on the phone.] For the avoidance of doubt: Cyrix SLC/DLC are 386 to 486 upgrade chips. I'm talking about real Cyrix 486DX2 (and DX4) parts, which IMHO should *not* have their caches disabled. -- Bob Bishop (0118) 977 4017 international code +44 118 rb@gid.co.uk fax (0118) 989 4254 between 0800 and 1800 UK