At 10:10 Uhr +0200 31.8.2007, Julio M. Merino Vidal wrote:
>> The {Quadra,Performa} 630 has a PDS connector ('030 style PDS,
>> afair), and
>> a Communications slot (style II). No Nubus, and unlike the 610 no
>> optional riser card with Nubus bridge.
>
>Oh :(  Then, out of curiosity, why the NetBSD kernel attaches a nubus0?

Well, what is Nubus? It's a set of conventions for a memory layout - a
number of slots, and 16 MBytes per slot, neglecting 24 bit mode and slot
superspace for now - and on how to find and use a card configuration ROM in
each slot.

Note that so far I didn't mention the word "hardware".

You cannot "probe" the Nubus itself, because there are no registers to
configure (the Quadra Nubus controllers have one or two, but we don't use
them for anything). We just assume it's there. You can scan the Nubus slots
for devices, though - that's what the code in arch/mac68k/nubus/nubus.c
does.

The first Nubus equipped Macs - The II, the IIx, the IIcx - had video on
Nubus cards. When Apple came up with the IIci that had onboard video, they
found it easiest to use existing interfaces and conventions, and mapped the
onboard video into a "pseudo slot". Apple recommended the same practice for
PDS cards in Nubus-less Macs like the SE/30 for more uniform driver
software. I'd guess that when you plug an Ethernet card into your Quadra
630's PDS, it will show up as Nubus card, simply because it has a proper
declaration ROM in the proper place.

On Nubus video cards... I just found that my last Mac without onboard
("intvid") video, a IIcx, has silently died. Unfortunately, the mac68k
kernel does not ignore an inactive onboard video controller, as it should -
the Booter probably ought to communicate the fact. Right now, when I try to
boot a Quadra 700 to Nubus video, it hangs when probing intvid, and never
gets to the Nubus video.

Could you configure a test kernel with only Nubus video, please?

	hauke

--
"It's never straight up and down"     (DEVO)