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Newsgroups: comp.os.386bsd.questions Path: sserve!newshost.anu.edu.au!munnari.oz.au!goanna.cs.rmit.oz.au!aggedor.rmit.EDU.AU!harbinger.cc.monash.edu.au!msuinfo!agate!usenet.ins.cwru.edu!nigel.msen.com!math.fu-berlin.de!news.th-darmstadt.de!zib-berlin.de!easix!flyer.GUN.de!flatlin!bad From: bad@flatlin.ka.sub.org (Christoph Badura) Subject: Re: PCI SCSI for NETBSD Date: Sat, 26 Feb 1994 23:48:30 GMT Message-ID: <CLuvGu.5Lv@flatlin.ka.sub.org> References: <baier.2.000933A6@risc1.ccso.cim.ch> <michaelv.761848129@ponderous.cc.iastate.edu> <CLLM44.3M2@obiwan.uucp> <michaelv.761882391@ponderous.cc.iastate.edu> Organization: Guru Systems/Funware Department Lines: 48 In <michaelv.761882391@ponderous.cc.iastate.edu> michaelv@iastate.edu (Michael L. VanLoon) writes: >All of the current models should have this feature. Basically, it >uses the mailboxes in a round-robin fashion. This breaks the old >driver because the card starts looking for disk transactions where >there are only empty mailboxes and it never gets around to the >intended transactions since the driver doesn't write them out in >round-robin order. I presume you meant it *scans* the mailboxes in a round-robin fashion. That's a very old feature. In fact, this at least dates back to the AHA1542A. This was clearly documented to be the case as of 12/31/91 (the oldest 742A technical reference manual I have at hand) and that's well before the 742A driver was written. In any case, from my inspection of Julian's code I'd say that the code deals properly with this situatation by issueing a Start Mailbox Command opcode to the adapter whenever it places a request into an outgoing mailbox. The fact that older as well as recent adaptors work flawlessly with Julian's code makes me wonder what this alleged change in firmware would be about. However, I understand that the BT-946C has a completely new BIOS and firmware and therefore might behave different than than the other models. >I saw a comment in Julian's drivers that said this >feature appeared first at firmware version 3.31, but it may have been >optional back then -- it is now the default behaviour in any current >cards. I was unable to find a comment to this extend in the NetBSD and you driver. I wonder what it said. Anyway, the behavior never was optional. >I have a new bt driver that fixes this for NetBSD-current. I don't know what the your modifications are supposed to fix. From looking hard at the diffs all I can say is that the mods for sure burn a lot more cycles in the driver. And, to me anyway, for no apparent reason. I'd very much like to hear a detailed explanation of the new behavior and why your mods fix it. -- Christoph Badura bad@flatlin.ka.sub.org +49 721 606137 Es genuegt nicht, keine Gedanken zu haben; man muss auch unfaehig sein, sie auszudruecken. - Karl Kraus