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Path: sserve!newshost.anu.edu.au!munnari.oz.au!bunyip.cc.uq.oz.au!harbinger.cc.monash.edu.au!msuinfo!agate!library.ucla.edu!europa.eng.gtefsd.com!howland.reston.ans.net!vixen.cso.uiuc.edu!uxa.cso.uiuc.edu!rkb55989 From: rkb55989@uxa.cso.uiuc.edu (Rafal Boni) Newsgroups: comp.os.386bsd.development Subject: Re: [FreeBSD 1.0R] DMA Problems? Date: 17 Dec 1993 21:59:15 GMT Organization: University of Illinois at Urbana Lines: 53 Message-ID: <2eta3j$6t9@vixen.cso.uiuc.edu> References: <2eopau$hde@vixen.cso.uiuc.edu> <jmonroyCI6HqF.Hxu@netcom.com> NNTP-Posting-Host: uxa.cso.uiuc.edu jmonroy@netcom.com (Jesus Monroy Jr) writes: >Rafal Boni (rkb55989@uxa.cso.uiuc.edu) wrote: >: j@uriah.sax.de (J Wunsch) writes: >: [stuff J"org and Terry were debating deleted...] >: >In fact, i'm also experiencing lotta DMA overruns when attempting to do >: >some floppy IO while some heavy compile job is running. This is in a box >: >with an Adaptec SCSI, and i didn't track it down whether it's the CPU >: >load that causes the trouble (would really look strange to me), or if >: >it's the heavy disk IO that happens while compiling. >: I would be tempted to say that the Adaptec is at fault... I have a >: 3Com 3c507 Ethernet card in my machine, and the docs SPECIFICALLY >: mention the fact that Adaptec's 154x may cause problems for the >: Ethernet card's DMA reads/writes.... Later 3Com updated some of >: the [I would guess] DMA related circuitry to be able to handle longer >: timeouts or something of that nature... >: > Most problems encountered with Adaptec's 154X and ethernet > cards are I/O port, IRQ and DMA channel conflicts. 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... > Both 3Com cards and Adaptec's card are configurable to many > setting. Getting them to conflict is very easy. I would > not be so quick to blame the AHA card. FTP to ftp.3com.com and you too can read 3Com's tech notes on the subject... While it may not be 100% Adaptec's fault [in this case, 3Com relaxed their own timing reqirements to allow both of the cards to work], it definitely is something that was caused by the Adaptec's holding on to the bus for too long... >-- >Jesus Monroy Jr jmonroy@netcom.com >Zebra Research >/386BSD/device-drivers /fd /qic /clock /documentation >___________________________________________________________________________ ---------------------------------------------------------------------------- Rafal Boni I'm a student -- nothing I say holds any value! r-boni@uiuc.edu This message has not been endorsed by the Surgeon General, nor the University of Illinois. All opinions are my own, not UIUC's.