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Xref: sserve comp.os.386bsd.questions:1546 comp.unix.bsd:11810 Path: sserve!newshost.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!lll-winken.llnl.gov!fastrac.llnl.gov!usenet.ee.pdx.edu!acacia!rgrimes From: rgrimes@acacia (Rodney W. Grimes) Newsgroups: comp.os.386bsd.questions,comp.unix.bsd Subject: Re: patch support for Chris' com drivers ? Date: 13 Apr 1993 05:23:13 GMT Organization: Portland State University Lines: 57 Message-ID: <1qdio2$mjf@walt.ee.pdx.edu> References: <C5D4sw.B3B@constellation.ecn.uoknor.edu> NNTP-Posting-Host: acacia.cs.pdx.edu ngorelic@speclab.cr.usgs.gov.cr.usgs.gov (Noel S. Gorelick) writes: : Rodney Grimes (rgrimes@agora.rain.com) wrote: : > : >Chris, please don't contridict me, you have not even seen my GENERICISA : >config file. Yes the support for COM3 and COM4 is there, no they do not : >use shared interrupts. I used the most common alternate IRQ's for them : >IRQ2 and IRQ5, this has the largest hardware support. I am running a kernel : >config just that way. I have 2 16550 ports at std com2 and com4, irq5, irq2 : >respectfully. And 2 16450 ports at std com1 and com3. It works and it has : >since 0.1. : : Umm, what about those of us that can't spare irq2 and/or irq5? Are there : shared interrupt drivers available? Heres what I currently have: The reason I chose IRQ2 and IRQ5 is that is what most COM boards allow as alternates, not so much as what is not used. The bad thing is that shared interrupts require special hardware design to be done correctly, and I know of no boards that are designed correctly. This is an electronic level issue, that has to do with the type of driver used to drive the IRQ signal. : : IRQ 1: pc0 (keyboard) : IRQ 3: com2 : IRQ 4: com1 : IRQ 5: wt0 (tape drive) : IRQ 6: fd0 (floppy drive) : IRQ 10: we0 (ethernet card) : IRQ 11: as0 (scsi controller) : IRQ 13: npx (what the heck is this?) That is the interrupt for the FPU chip, if you do not have an FPU it is used by the math emulation software. : IRQ 14: wd0 (Do I even NEED this if I have a scsi drive only?) Nope, you don't need that if you do not have a wd disk. You can gen a kernel without the wd driver and it will work just fine. Infact you could free up IRQ11 by moving your as0 device to IRQ14 with a properly gened kernel. : : That leaves 2,7,8,9 and 12 free. Anything specific have to go in 7,8,9 or 12? First, 2==9, they are one and the same. Second, 7 is reserved for lpt. Third, 8 is reserved for the Real Time clock. 9==2 and is used for lots of things..., and finally 12 is used by lots of things too, bus mice, some disk controllers, etc etc... : : (I know neither my tape controller nor my ethernet card will go at anything : above 10, leaving actually only 4 free slots, so... I COULD do it without : shared interrupts, given that my com cards will let me put them at 2 and 5) : : Sorry if these are stupid questions... I'm a software guy. this hardware : stuff is new to me. You have a real tough one to deal with there... maybe get an 8013 ethernet board so you can run it at IRQ12...