*BSD News Article 36680


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Newsgroups: comp.os.386bsd.questions
Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!msuinfo!agate!ames!pacbell.com!amdahl!netcomsv!c-cube.com!news
From: eh@xvnews.unconfigured.domain (Ernest Hua)
Subject: How to set up 2 serial I/O plus 1 modem?
Message-ID: <Cx9tr7.10x@c-cube.com>
Sender: news@c-cube.com
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Reply-To: eh@xvnews.unconfigured.domain
Organization: C-Cube Microsystems
Date: Thu, 6 Oct 1994 21:45:06 GMT
Lines: 38

I am trying to configure a kernel that will support 2 serial I/O lines plus 1
internal modem.

I have:

    486-DX2-66 256K 16M
    Number Nine GXE64Pro 2M
    Bus Logic BT445S SCSI2
    Practical Periperals 14400FX
    2S/1P/1G

I know that the PP14400FX will support COM1-4 at the "normal" IRQ's:

    COM1  IRQ4
    COM2  IRQ3
    COM3  IRQ4
    COM4  IRQ3

However, FreeBSD will not allow multiple devices at the same IRQ except if
this "multiport" feature is enabled.  If I leave the 2 serial ports at COM1
and COM2 and try to put the modem port at COM3 or COM4, then no matter how
I configure the kernel (with or without "multiport"), it does not work.

If I configure the hardware so that the serial ports are on COM1 and COM3,
and I put the modem on COM2, then at least the modem works and COM3 works,
but COM1 does not seem to work.

What am I doing wrong?  Is the "multiport" feature very very specific to
these special purpose serial boards, or could it be used to generically
allow for shared IRQ's?  If the former, how does one allow for shared IRQ's
on a two serial ports?

Ernest Hua
C-Cube Microsystems
ernest.hua@c-cube.com