From: John E. <sh...@co...> - 2003-06-30 20:27:01
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On Mon, Jun 30, 2003 at 01:43:32PM -0500, Richard Lynch wrote: > My GREEN and ORANGE cards are both snagging IRQ 12, and they are not working. PCI cards should be able to share the same IRQ if they both play nice and use interrupt sharing. There may be some performance loss on PCI throughput but you probably will not notice that unless they are Gigabit cards. > I can swap my RED/GREEN and RED, on IRQ 9, always works. > > I've been studiously reading all kinds of fun (not!) stuff about IRQs > and such-like. > > The IPCop FAQ says: > "You may need to download a DOS utility from the manufacturer's > website to find out what the card is set to, and to change it if it > conflicts with another card in the same box." > > However, this resource, by Becker, who as far as I can tell, wrote a > zillion Linux drivers and sure ought to know what he's talking about, > claims: > http://www.scyld.com/expert/irq-conflict.html > "PCI cards do not select their own IRQ line. Instead they can only > select one of four "interrupt pins", which are mapped by the > motherboard chipset to IRQ lines. I'll stress this again -- only the > motherboard BIOS knows how the INT to IRQ mapping is wired, and thus > only the BIOS can change the IRQ mapping for the card. The IRQ > mapping is usually configured at boot time by the PCI BIOS setup, > with the the exact assignment algorithm being BIOS-specific." > > So, is the IPCop FAQ perhaps a trifle imprecise, and referring to > IRQs when, in fact, it should be referring to the "interrupt pins" > that can be set by the manufacturer? Nope, they are talking about different things. Donald Becker is discussing how PCI cards in great detail. The FAQ is noting that some cards (usually ISA ones) are not automatically configured or detected and so you need a setup utility. > On top of that, is it not a little presumptuous that I'll *HAVE* a > DOS box around? I don't. Just use a DOS boot disk, aka "Windows Emergency Repair Disk" from Windows 95 or 98. > I don't really have a lot of colleagues who would be keen on my > waltzing over to their house, opening up their computer, installing > some hardware, and running some DOS utility on it either. I mean, > yeah, I *could* find somebody willing to let me do that, but criminy, > that seems like a bit much to ask, don't you think? > > Meanwhile, my problem is that I have purchased some $10 NICs > manufactured by "Fast Ethernet Controller Provider Inc." > There is no web-site in the NIC docs. So they are cheap, no name, no support. Is there anything to differentiate them from a piece of junk ? First you'll need to find out chipset they use, which can sometimes be written on the chips. Otherwise try querying the PCI info (Device Manager in Windows or "cat /proc/pci" in Linux/IPCop). Secondly you'll need to check that there is a driver for that card in the Linux kernel. If you still don't know you the chipset and autodetection doesn't work then you could take a guess for the common cheapos - NE2000 or Realtek 8139. > They specifically suggest changing the INT (presumably the "interrupt > pins" referred to by Mr. Becker) in the BIOS to "INT A". I've never had to fiddle with INT settings in the BIOS to get a network card to work, and I've worked with some really wierd ones. Sound like those cheap network cards maybe somewhat broken when it comes to PCI Plug-and-Play IRQ allocation or interrupt sharing. Another possibly is they are just broken - have you tested each of them on there own ? > So I'm back to the BIOS. > > Alas, I don't really understand the BIOS screens. > > There are about 30 lines I can change from "PnP" to "Legacy ISA" > > There is one (1) place I can change the INT from A to B. > > I've got *TWO* cards, and I need *ONE* of them to be INT A and the > *other* to be INT B. > I've tried altering the line number 12 to "Legacy ISA" in the hope > that the NICs would then try other IRQs. They did. The same one. > :-( That is correct behaviour, "Legacy ISA" means do not allocate to a PCI card because there's an ISA card on that IRQ that does not talk PnP. So there are less available IRQs for the PCI devices and it is more likely that two cards will share the same IRQ. > I didn't try INT B yet, but I'm not feeling real hopeful. Neither am I. > Countless 'net searches are leaving me high and dry, at best. > > Model: XEN3200WN > > Help! My best recommendation is to return the cheap pieces of junk that are being sold as PCI cards on grounds that they do not seem to following the PCI specs. Then get a good brand name card such as 3com 905 or Intel EtherExpress Pro. It will cost you about 20 more US dollars and save you weeks of grief. -- #--------------------------------------------------------# | John Edwards Email: Joh...@uk... | | | | "SEP is intended as a management routing protocol, | | and should not be used in a production enviroment." | #--------------------------------------------------------# |