Path: utzoo!attcan!uunet!husc6!bloom-beacon!mit-eddie!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: <11932@dartvax.Dartmouth.EDU>
Date: 24 Jan 89 16:42:54 GMT
References: <1907@ast.cs.vu.nl>
Sender: news@dartvax.Dartmouth.EDU
Reply-To: stevel@eleazar.dartmouth.edu (Steve Ligett)
Organization: Dartmouth College, Hanover, NH
Lines: 23

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.

Or, read out the first status byte *only*, in disk_int.  It is reading
this status byte that turns off the interrupt request from the fdc.

My PC isn't yet up to running Minix, but here's what I'd try:

1.  On receiving an interrupt, read the main status reg (3f4).
    If both bits 4 and 5 (NON_DMA & FDC_BUSY) are zero, a Seek
    or Recalibrate caused the interrupt, so issue the Sense
    Interrupt Status command.

2.  Either call fdc-results or read out status reg 0 to turn off
    the interrupt.  Return the result(s) in the message to the floppy
    task.

3.  Modify the code after each
    receive (HARDWARE, &mess);
    in the floppy task to handle the results properly.
Steve Ligett       steve.ligett@dartmouth.edu or
(decvax harvard linus true)!dartvax!steve.ligett