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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!msunews!news.mtu.edu!newsxfer.itd.umich.edu!newsxfer3.itd.umich.edu!howland.erols.net!cam-news-hub1.bbnplanet.com!cpk-news-hub1.bbnplanet.com!news.bbnplanet.com!newsfeed.nacamar.de!supernews.com!bighorn.accessnv.com!jca From: jca@bighorn.accessnv.com (J.C. Archambeau) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: Am5x86/P75 WB caching... Date: 21 Mar 1997 01:27:37 GMT Organization: All USENET -- http://www.SuperNews.com Lines: 30 Message-ID: <5gso69$eqb@usenet88.supernews.com> References: <5gnrql$2ut@usenet88.supernews.com> <5gpmhp$hc7@verdi.nethelp.no> NNTP-Posting-Host: bighorn.accessnv.com X-Newsreader: TIN [version 1.2 PL2] Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:37500 Steinar Haug (sthaug@nethelp.no) wrote: :| I just upgraded the CPU in my EISA/VLB motherboard from an i486DX/33 to :| an AMD Am5x86/P75 (133). FreeBSD (2.2-BETA) properly indentifies the CPU, :| but it states that the L1 cache is in write through mode at bootup. Does :| FreeBSD disable write back caching of the Am5x86? If it does, what :| define or kernel configuration parameter do I need to change? : FreeBSD works fine with writeback. Here's the boot info from a 5x86-133 : running in an ASUS PVI-486SP3 motherboard: : FreeBSD 2.2-BETA_A #1: Sun Jan 12 15:25:39 MET 1997 : sthaug@bizet.nethelp.no:/local/usr/src/sys/compile/GATE : Calibrating clock(s) relative to mc146818A clock ... i8254 clock: 1193220 Hz : CPU: AMD Am5x86 Write-Back (486-class CPU) : Origin = "AuthenticAMD" Id = 0x4f4 : real memory = 25165824 (24576K bytes) : avail memory = 22835200 (22300K bytes) : At least on this motherboard you need to enable writeback with a jumper. Is there a way to force FreeBSD to enable write back caching though? It may not be enabling it for my particular chipset (SiS EISA chipset). I know that write back is working from MS-DOS and Win 3.x because of the results of various utilities (i.e. cachchk6). -- /* | Spam violation - e-mail dumped... ** Internet: jca@accessnv.com | Don't blame me, I didn't vote for Clinton. ** jca@anv.net | Intel is the word for 'errata.' */