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Path: sserve!manuel.anu.edu.au!munnari.oz.au!sgiblab!swrinde!cs.utexas.edu!uunet!mcsun!Germany.EU.net!unidui!du9ds3!veit From: veit@du9ds3.uni-duisburg.de (Holger Veit) Newsgroups: comp.unix.bsd Subject: Re: How do I enable COM3 and COM4? Date: 22 Oct 92 07:56:51 GMT Organization: Uni-Duisburg FB9 Datenverarbeitung Lines: 53 Message-ID: <veit.719740611@du9ds3> References: <1992Oct15.162922.24566@fcom.cc.utah.edu> <1992Oct19.032151.29724@cs.cornell.edu> <veit.719567281@du9ds3> <1992Oct20.143735.1331@netcom.com> Reply-To: veit@du9ds3.uni-duisburg.de NNTP-Posting-Host: du9ds3.uni-duisburg.de In <1992Oct20.143735.1331@netcom.com> abe@netcom.com (David Abercrombie) writes: >In article <veit.719567281@du9ds3> veit@du9ds3.uni-duisburg.de writes: >>In <1992Oct19.032151.29724@cs.cornell.edu> cchase@cs.cornell.edu (Craig Chase) writes: >> >>>You might also want to edit isa.h to add >>>#define IO_COM4 0x2e8 >>>#define IO_COM3 0x3e8 >> >>>and then use in the config file >>>device com2 at isa? port "IO_COM3" tty irq 4 vector comintr >>>device com3 at isa? port "IO_COM4" tty irq 3 vector comintr >> >>>p.s. mknod /dev/com2 c 8 2 ; mknod /dev/com3 c 8 3 >> >>This is the obvious "solution", but will cause really dirty problems, provided >>you do not remove the lines for com1 and com2 (or com0/com1, depending how >>they are called). Usually they occupy the irq3 and irq4 lines. So you >>get an interrupt clash for the serial lines, with the effect that data may >>get lost in the situation where two ports on the same irq call for service. >>Don't use the above patch without modifying the com driver irq service >>to take care for these multiple events, even if anyone claims that "this >>works for me". In real situations, it will fail miserably. >> >>Holger [...] >I just got an STB 4-COM serial card with the equivalent of >four 16550A UARTS on it. It has 40 jumpers that allow you >to choose from a list of eight different i/o port addresses >and eight different IRQ lines for any of the four ports. >I can easily find unused IRQ lines on my system so that I can >have four ports working. I just got this card and am having >some minor difficulties, but will let you all know more details >once I have had a chance to really test it. >-- >Dave Abercrombie lyra!abe@infoserv.com >Oakland, CA -- or -- >(510) 652-7131 abe@netcom.com In this case there is a chance to get four lines working without problems. I was speaking of the $10-type multi-I/O cards (8bit slot) that often allow jumpering the COM lines to COM3/COM4 (using the above port addresses). The best would be a board which has its own Interrupt controller to be chained to one of the free interrupts. This, however needs some modifications in /sys/i386/isa.* Holger -- | | / Dr. Holger Veit | INTERNET: veit@du9ds3.uni-duisburg.de |__| / University of Duisburg | "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX | | / Dept. of Electr. Eng. | Sorry, the above really good fortune has | |/ Inst. f. Dataprocessing | been CENSORED because of obscenity"