Return to BSD News archive
Path: sserve!newshost.anu.edu.au!munnari.oz.au!constellation!aardvark.ucs.uoknor.edu!ns1.nodak.edu!netnews.nwnet.net!usenet.coe.montana.edu! saimiri.primate.wisc.edu!sdd.hp.com!ux1.cso.uiuc.edu!howland.reston.ans.net! usc!sol.ctr.columbia.edu!news.kei.com!news.byu.edu!cwis.isu.edu!fcom.cc.utah.edu!cs.weber.edu!terry Newsgroups: comp.os.386bsd.questions Subject: Re: Modem setup on 386BSD [and a further QUESTION] Message-ID: <1993May28.195017.23712@fcom.cc.utah.edu> From: terry@cs.weber.edu (A Wizard of Earth C) Date: Fri, 28 May 93 19:50:17 GMT Sender: news@fcom.cc.utah.edu References: <1993May27.043819.13711@mcshub.dcss.mcmaster.ca> <CJB.93May28115334@thrip.cs.uq.oz.au> Organization: Weber State University (Ogden, UT) Lines: 27 In article <CJB.93May28115334@thrip.cs.uq.oz.au> cjb@cs.uq.oz.au (Christopher J Biggs) writes: >Question: Has anyone got a driver that will drive a multi-IO card at IRQ 2&3 >and an internal modem on 2or3 (it wont go anywhere else!!). I haven't seen one yet -- and, unless you have a very special modem and com card, you aren't going to be able to write one -- ever. Interrrupt sharing depnds on being able to ask all devices using the interrupt if they were the one that caused the interrupt -- basically, the interrupt is a "data available" flag. Most serial hardware doesn't support a flag to indicate data available since last read. Multiport boards, on the other hand, *do* support flagging the interrupt source, *but* require a driver that knows about the flagging mechanism. Some UARTS (but not the low-end ones in most PCs) support a status register indicating "data in FIFO". This can be used the same way as a hardware specific interrupt origin flag (like most multiport boards use), but the hardware specific flags are not frequently in the same place between multiple hardware vendors, so a special driver is normally needed with at least a vendor- (and potentially a product-) specific piece of code to query interrupt origin. Terry Lambert terry@icarus.weber.edu --- Any opinions in this posting are my own and not those of my present or previous employers.