Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!bu-cs!dartvax!eleazar.dartmouth.edu!stevel
From: stevel@eleazar.dartmouth.edu (Steve Ligett)
Newsgroups: comp.os.minix
Subject: Re: PS/2 level-triggered interrupts
Message-ID: <12009@dartvax.Dartmouth.EDU>
Date: 29 Jan 89 16:31:06 GMT
References: <1907@ast.cs.vu.nl> <11932@dartvax.Dartmouth.EDU> <1974@ast.cs.vu.nl>
Sender: news@dartvax.Dartmouth.EDU
Reply-To: stevel@eleazar.dartmouth.edu (Steve Ligett)
Organization: Dartmouth College, Hanover, NH
Lines: 36

In article <1974@ast.cs.vu.nl> ast@cs.vu.nl (Andy Tanenbaum) writes:
>In article <11932@dartvax.Dartmouth.EDU> stevel@eleazar.dartmouth.edu (Steve Ligett) writes:
>>I think the best way of fixing the interrupt problem for floppy disks is
>>to call fdc_results within disk_int and return the status bytes in the
>>message.
>
>I am not sure if this is a suitable solution in general, i.e., one probably
>needs analogous hacks for the printer, ethernet, hard disk, serial port, etc.,
>and that comes close to putting a fair amount of the logic in the interrupt
>routine, something that has been avoided so far.
>
>Andy Tanenbaum (ast@cs.vu.nl)

I should have said why I suggested that option.  There were 4 options
that I looked at:

1.  Read out the main status reg of the fdc.  Sadly, that didn't affect
the INT line.

2.  Mask interrupts in the 8259.  That's what Steve Ackerman has
working, I believe.  The problem with that is that you've now thrown
away the reason for level-sensitive interrupts, and I thought it was too
early in the game to give them up.

3.  Read out a status reg as I suggested above.  I didn't mean to say I
thought it was a great idea, just that I hadn't found one better.

4.  Set the bit in the DOR (3f2) to mask interrupts.  Now, this one
sounds good.  However, it didn't seem to work, when I tried it in DEBUG.
But, I think I goofed in my testing, and will try again later this week,
unless someone else has tried and posts results.  This way sounds like
the best way that I can see - it masks interrupts from the fdc, but
nothing else.  More later.

Steve Ligett       steve.ligett@dartmouth.edu or
(decvax harvard linus true)!dartvax!steve.ligett