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Newsgroups: comp.os.386bsd.development Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!elroy.jpl.nasa.gov!decwrl!netcomsv!netcom.com!jmonroy From: jmonroy@netcom.com (Jesus Monroy Jr) Subject: Re: [FreeBSD 1.0R] DMA Problems? Message-ID: <jmonroyCIB20s.FF8@netcom.com> Organization: NETCOM On-line Communication Services (408 241-9760 guest) X-Newsreader: TIN [version 1.1 PL8] References: <CI9EC4.AoB@genesis.nred.ma.us> Date: Sun, 19 Dec 1993 23:17:16 GMT Lines: 26 Steve Gerakines (steve2@genesis.nred.ma.us) wrote: : I have neither an Adaptec nor a 3c507 and I'm the one who asked about : this originally. Jesus was right (in this case anyhow :-)) when he said : it had to do with the NEC 765A not being buffered and not receiving an : ACK in time. (Sounds like this is basically what you're saying as well.) : A couple of other people have confirmed that overruns during FDC DMA writes : is a known and documented problem. : Is there any known way to get around this other than just doing retries : (over and over) or modifying your hardware? : Previously I had stated that the problem stemmed from the possibility that the "RAM refresh" process had priority over the "FDC transfer". If this is true then (I beleive) there is no way around this problem (except by new hardware). If however, the problem stems from another possible hardware "incompatibility" then maybe that should be the answer. Yeeck... can't beleive I said that.. -- Jesus Monroy Jr jmonroy@netcom.com Zebra Research /386BSD/device-drivers /fd /qic /clock /documentation ___________________________________________________________________________