On Sun, 30 Jul 2000, Tony Mantler wrote:

> >Also, if there's anyone on the list who is familiar with IDE on the Quadra
> >630, from an interrupt standpoint, please drop me a line.  I'm working on
> >the Performa 6214 and family for MkLinux, and the hardware is very
> >similar.  As far as I can tell, if I trigger the interrupt handler
> >manually (e.g. by hitting a key), things work (i.e. polling the F108
> >register shows an IDE intr occurred), but the IDE hardware never actually
> >starts the interrupt handler on its own, which makes me think that there's
> >something about the interrupt levels on 68k that I just don't understand
> >yet.  Anybody?
> 
> Mmm, triply cascated interrupts are always fun.

Yup.


> IIRC the F108 should
> cascade through a slot interrupt on VIA2 (slot E I think, but I could be

Via2 Port B, slot F as far as I can tell.  Slot E is the PDS slot.  Slot
interrupts then cascade into Bit 1 on Via2 IFR.


> wrong), meaning that if you miss ANY slot interrupt, they'll ALL be gone
> forever.

That's the thing, though.  We never get any slot interrupts -- not even
the first one.  They never make it to VIA2 IFR.  VIA2 reads 0x00 at every
interrupt, indicating that nothing is ever reaching it.  I don't believe
it's even reaching VIA2 portB, either, sicne I see to recall that never
changing values.


> I don't recall if the F108 has the same bogosity internally when
> handling all the different interrupts it generates, but it might be worth
> checking out.
> 
> I'd say check to make sure your slot ints aren't being hosed, (ie: make
> sure you're never leaving the slot interrupt handler with any slot ints
> still asserted) and you should be most of the way to getting all your
> interrupts.

Yeah, but as far as I can tell, portB (where the slot ints come in) is
read-only, i.e. the interrupts get cleared elsewhere.  Am I
misinterpreting that?  If so, then I probably need to init Port B in some
way.  Any idea what the magic value is?


David

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