Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!rochester!rutgers!att!alberta!ubc-cs!van-bc!sl
From: sl@van-bc.UUCP (pri=-10 Stuart Lynne)
Newsgroups: comp.unix.microport
Subject: Re: 16550A in uport 3.0e ('386)
Message-ID: <2226@van-bc.UUCP>
Date: 13 Feb 89 20:01:14 GMT
References: <5111@b-tech.ann-arbor.mi.us> <379@twwells.uucp>
Reply-To: sl@van-bc.UUCP (pri=-10 Stuart Lynne)
Organization: Wimsey Associates, Vancouver, BC.
Lines: 20

In article <379@twwells.uucp> bill@twwells.UUCP (T. William Wells) writes:
>In article <5111@b-tech.ann-arbor.mi.us> zeeff@b-tech.ann-arbor.mi.us (Jon Zeeff) writes:

>I've always had problems with my modem locking up, in that the modem
>transmits to the system but the system doesn't hear it. This has not
>changed since I installed the 16550A. However, this has never brought
>my system to a halt; all it does is require me to reboot if I want my
>modem to work correctly. I'm almost certain that this is something
>wrong with my I/O card.

Sounds like you're driver isn't servicing interrupts properly. If the
interrupt service routine doesn't completely clear all sources of the
interrupt then you will never get another successful interrupt for that
interrupt line.

This is a function of the PIC, it is level triggerred; and if you never
bring the level down it cannot see someone else bringing it high. 

-- 
Stuart.Lynne@wimsey.bc.ca {ubc-cs,uunet}!van-bc!sl     Vancouver,BC,604-937-7532