Date: Fri, 17 Jan 1997 02:07:09 -0500 (EST) From: Kenneth Merry <ken@housing1.stucen.gatech.edu> To: drussell@internode.net (Doug Russell) Cc: smp@freebsd.org Subject: Re: Adaptec 3940UW and SMP Message-ID: <199701170707.CAA23020@housing1.stucen.gatech.edu> In-Reply-To: <1.5.4.32.19970117065159.0072fe60@internode.net> from Doug Russell at "Jan 16, 97 11:51:59 pm"
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Doug Russell wrote... > At 01:10 AM 1/16/97 -0500, you wrote: > > >Slot 1: Matrox Millenium (IRQ 11) > >Slot 2: Adaptec 3940UW (IRQ 10) > >Slot 3: Empty (IRQ 9) > >Slot 4: SMC 10/100 card (IRQ 15) > >Slot 5: Empty (shares IRQ w/ slot 4) > > > The bad thing, though, is that with this setup, it means I won't be > >able to put anything in slot 3. And if I put anything in slot 5, it'll > >have to be able to share an interrupt with the SMC card. > > Aren't you stuck, no matter what? If the 3940 needs to use both int A and B > of it's slot, doesn't that necissarily mean that you can only run 3 cards > (assuming no interrupt sharing)? Actually... Does the video card REALLY > use the interrupt? Don't most cards have a jumper to disable interrupt use? You're right, it turns out that the video card didn't really need the interrupt... > If it doesn't use IRQ11, can't you put the Adaptec in slot 4, so it uses 15 > and 11? What does the ABCD map look like on slot 5? Is it the same as slot > 4? Slot 4 is A->15, B->11, C->10, D->9, right? Is 5 the same for all 4? The board only uses INT A, according to the manual. > I'm also assuming the 3940 can't share an interrupt with itself, (the other > half of itself, I mean... :-) ) otherwise they wouldn't have made it use INT > B as well, right? Well, it does use INT A for both channels: ahc0 <Adaptec 3940 Ultra SCSI host adapter> rev 0 int a irq 11 on pci1:4 [ ... ] ahc1 <Adaptec 3940 Ultra SCSI host adapter> rev 0 int a irq 10 on pci1:5 > Hmmm... Unfortunately I don't know enough about the PCI spec to know how > the whole INT A..D, mapping to ISA IRQs, etc. works. I guess I need to do > some reading. :-) I assume that the four (normal, in your case 5) PCI > slots always use the same physical lines for each slot. ie, you cannot > somehow map an additional line onto one of the slots. yes? There are only four IRQ's for 5 slots. Slots 4 and 5 share the same IRQ. So in order to have cards in both 4 and 5, I would assume that the cards would have to be able to share interrupts, or one of the cards would just not use an interrupt. (like a video card, perhaps) This is the setup I have now, it seems to work fine: Slot 1: Adaptec 3940UW (IRQ 11) Slot 2: Matrox Millenium (IRQ 10) Slot 3: Empty (IRQ 9) Slot 4: SMC 10/100 card (IRQ 15) Slot 5: Empty (shares IRQ w/ slot 4) The second channel of the 3940 grabs IRQ 10, and video still works fine. > Too bad you can't just jumper things around like you can with ISA interrupts. > My friends love this machine.... :-) [ ... ] Yeah, in a way I miss the way that you could unambiguously hardwire things to one specific interrupt, and not have to worry about some setup program mucking things up. At least I have the ability to hardwire specific interrupts to specific slots, though. The BIOS in this thing also lets you reserve specific interrupts for "legacy" ISA cards. The rest of the interrupts are fair game for the bios' PnP setup code. Ken -- Kenneth Merry ken@ulc199.residence.gatech.edu Disclaimer: I don't speak for GTRI, GT, or Elvis.
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