Path: utzoo!attcan!uunet!mcvax!hp4nl!botter!star.cs.vu.nl!ast
From: ast@cs.vu.nl (Andy Tanenbaum)
Newsgroups: comp.os.minix
Subject: Re: Help! Minix 1.3 & PS/2 Model 80
Message-ID: <1906@ast.cs.vu.nl>
Date: 16 Jan 89 22:22:29 GMT
References: <1023@uvm-gen.UUCP>
Reply-To: ast@cs.vu.nl (Andy Tanenbaum)
Organization: VU Informatica, Amsterdam
Lines: 19

In article <1023@uvm-gen.UUCP> ackerman@uvm-gen.UUCP (Steve Ackerman) writes:
[discussion of the problem with the PS/2 Model 80].

I completely agree with Steve's analysis.  Since the operating system is read in
by bootblok.s, which makes BIOS calls, the hardware is presumably set up 
properly, including the 8259A.  For a PC, the 8259A is in edge-triggered mode.
After an interrupt, the device is re-enabled on line 1888 of the book.  You
get exactly one interrupt this way.

There must be an analogous statement to line 1888 for the microchannel.
My hope is that by adding a line

if (mca) port_out(somewhere, something)

around there, we can get exactly one interrupt, no more and no less.
If anyone who knows the PS/2, or for that matter, the 8259A, has any idea,
please post it.

Andy Tanenbaum (ast@cs.vu.nl)