Date: Fri, 18 Apr 1997 21:36:54 +0100 From: Bob Bishop <rb@gid.co.uk> To: KATO Takenori <kato@eclogite.eps.nagoya-u.ac.jp> Cc: freebsd-bugs@freefall.freebsd.org Subject: Re: kern/3292: Cyrix 486 performance problem Message-ID: <l03020904af7d8b1d935f@[194.32.164.2]>
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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
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