Subject: Re: PowerROM support in latest kernel
To: None <y0001006@ws.rz.tu-bs.de>
From: Scott Stevens <s.k.stevens@ic.ac.uk>
List: port-arm32
Date: 07/08/1997 12:24:53
Thomas Boroske writes:
 >
 > > We are talking to alsystems about a way of identifying PowerROM'd
 > > cards in a different way... this could get messy tho'.
 > 
 > I'm not sure. AFAIK, although the modules actually on the ROMs are 
 > identical (I believe) for all types of cards, I think that there are 
 > 'Morley' PowerRoms, 'Castle' PowerRoms etc... So the roms are different
 > anyway (perhaps it's just the type of eprom used, not the content), 
 > so perhaps it would be easy for them to change the ID.

This is what we thought...

 > Back to the actual problem: RiscBSD uses podule identification to select
 > the correct driver for any card found. In this case this breaks the support,
 > so wouldn't it be possible to make a kernel where you tell in the config
 > to just assume a card type x in slot y, not to test for it ?

Well you can get the kernel to only check specific slots. But all that
really does is only *present* a limited range of podules to the driver
for identification.

ie the probe process is something like this:

podulebus attaches and scans podules creating podule info strcutures.
Each unattached podules is passed to *every* possible driver that could
have a card in that slot.

The drivers simply check the ID and say whether they can drive it or
not. So the identification needs to be in the driver's match routine,
not in the parent podulebus routines.
 
 > Thomas Boroske

Cheers Scott

-- 
Scott Stevens, Network Services Group, Computer Centre, Imperial College
"Hey. The prospect of making love to a complete and total stranger is
just as galling to me, y'know? We gotta be completely professional about
this. Totally clinical and unemotional. So just lie back, relax and I'll
go and slip into my Spiderman costume."               - Lister, Red Dwarf