Subject: Re: S900/E100 progress (well, sort of)
To: Jeff Walther <trag@io.com>
From: Michael <macallan18@earthlink.net>
List: port-macppc
Date: 07/14/2004 20:11:14
Hello,

> I am not an OS programmer by any stretch of the imagination, but I am 
> a bit of a hardware guy.
Well, my hardware knowledge is from the good old Z80 time and I didn't 
really do anything more complicated than abusing a Z80SIO to talk to a 
PC keyboard - every in depth knowledge about PCI i might possess was 
acquired in the last few days while hacking NetBSD 2.0.

> It appears that Umax made use of this "phantom slot" and even gave the 
> card its name.
The card has two names - E100 and 'Mercury' - Mercury is probably the 
name UMAX gave it and E100 was inherited from Apple or so.

> Anyway, so it appears that Umax put five PCI devices on the single 
> Bandit in the S900.   There's Grand Central, the top two PCI slots, 
> the PCI-PCI bridge, and then support for the ethernet portion of the 
> E100 card.
scanpci confirms this - it sees bandit itself, the DEC bridge, 
JackHammer, a Voodoo3, GrandCentral and the 21140. Strangely all of 
them set to use pin 1.

> But Umax would still have needed a slot assignment in firmware for the 
> card, I think.   This is where the boundary of my knowledge lies. My 
> hazy understanding is that they were somehow able to grab this E100 
> artifact that is built into the firmware of these machines, to use as 
> the slot designation for the ethernet component of the card.
well, Apple's system profiler sees only 3 'slots' - the JackHammer, the 
graphics board and the bridge.

> Oh and going back a couple more messages, the four slots behind the 
> PCI-PCI Bridge all share the interrupt which would normally go to slot 
> C1.    So the interrupts for D2, E2 and F2 are available (as they 
> would be on any three slot machine) and I suspect that it is one of 
> those that was used for the E100 card.
Hmm, the SCSI part gets IRQ 23, the Voodoo3 24, the bridge 25, next 
device is Grand Central, so using 27 or 22 for the 21140 would be sort 
of logical?
( does this make any sense anyway? )

have fun
Michael