Date: Wed, 16 Jul 1997 14:16:11 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: smp@csn.net (Steve Passe) Cc: smp@FreeBSD.ORG Subject: Re: HEADS UP: EISA cards. Message-ID: <199707162116.OAA01479@phaeton.artisoft.com> In-Reply-To: <199707160551.XAA06975@Ilsa.StevesCafe.com> from "Steve Passe" at Jul 15, 97 11:51:00 pm
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> DESIGN DECISION: > > I am about to make a design decision that will forever-more make the use > of EISA cards that use the EISA chipset DMA circuit impossible in the SMP > kernel. I posted a rather long email about this several days ago but got ZERO > response. So I can conclude that either: > > a: everyone agrees with this decision. > OR > b: no one with such hardware read that far. c: there was a fiber cut in California which cut some of us off the net. I have EISA machines and I would prefer you not do this. As an alternative, I suggest that you assume the timer is properly forwarded on EISA hardware. EISA hardware can be easily detected. I also thought that Poul's machine, which was Jack Vogel's machine, was an EISA/PCI combo (actually, I know this for a fact, since I bought the ISA/PCI version of the board for spread testing with Jack). > I believe that we don't want to abandon the 8254, but instead should > abandon the DMA chaining INTs (who uses these anyways???) Then we > can program in a similar way, but instead pass the 8254 INT thru as > a regular INT. > ... > we need to make a policy decision as to whether we can say > bye-bye to the DMA chaining INTs. If I don't get thoughtful feedback on this > I will just nmake an arbitrary decision (which I suspect to be axing the DMA > INTs). I think the only situation needing them is non-busmaster EISA hardware > that does DMA via the motherboard chipset DMA registers. Please correct me > if I am wrong on this point. It wasn't clear from this that you would be spamming EISA hardware; note that I am not personally running EISA hardware, but I think it is a mistake to work around the problem on a platform where it's not necessary. Correct me if I'm wrong, and there's an EISA platform that exhibits the timer routing bug. Regards, Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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