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Newsgroups: comp.os.386bsd.development Path: sserve!newshost.anu.edu.au!munnari.oz.au!bunyip.cc.uq.oz.au!harbinger.cc.monash.edu.au!yeshua.marcam.com!usc!cs.utexas.edu!swrinde!gatech!bloom-beacon.mit.edu!noc.near.net!ceylon!genesis!steve2 From: steve2@genesis.nred.ma.us (Steve Gerakines) Subject: Re: [FreeBSD 1.0R] DMA Problems? Message-ID: <CI9EC4.AoB@genesis.nred.ma.us> Organization: Genesis Public Access Unix +1 508 664 0149 References: <2eopau$hde@vixen.cso.uiuc.edu> <jmonroyCI6HqF.Hxu@netcom.com> <2eta3j$6t9@vixen.cso.uiuc.edu> Date: Sun, 19 Dec 1993 01:48:03 GMT Lines: 21 Rafal Boni says: > Jesus, Jesus! Read my post.... It's not a configuration conflict! > What was happening is that the Adaptec would be stealing the bus for > too long of a time, thus causing the 3c507's DMA requests to time > out, overrun, underrun, etc. > > Nothing to do with the card's trampling each others' [DMA or I/O port > or IRQ] settings... 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? - Steve steve2@genesis.nred.ma.us