Date: Wed, 9 Jul 1997 19:06:11 -0700 (PDT) From: asami@cs.berkeley.edu (Satoshi Asami) To: se@FreeBSD.ORG Cc: bugtraq@polynet.lviv.ua, freebsd-hardware@FreeBSD.ORG Subject: Re: Q:PCI bridges-extenders supported Message-ID: <199707100206.TAA16248@silvia.HIP.Berkeley.EDU> In-Reply-To: <19970709195829.49457@mi.uni-koeln.de> (message from Stefan Esser on Wed, 9 Jul 1997 19:58:29 %2B0200)
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* In case this is not sufficient, there are some PCI
* extender boxes, but I never used one myself. ASAMI
* Satoshi has some experience with them.
I'm the ASAMI Satoshi Stefan is talking about. We got our PCI
expansion boxes from Bit3 (www.bit3.com). We haven't done much more
than a little testing, but they appeared to work ok.
The model we have has 7 slots in the expansion box; subtracting the 1
slot taken from the main bus for the connector card, each box adds 6
slots net behind three levels of PCI-PCI bridges. In the picture
above, "=" are the PCI slots. One of the slots in the expansion box
is designated for the connector card (marked with "*"). The bridge
chips are marked with "B". (Note the connector cable between the main
unit and the expansion box is also a separate PCI bus.)
Motherboard | expansion box
bus 0 | bus 1 bus 2
-=-=-=-=- -*-=-=-=-B-=-=-=-=-
| |
B---B
bus 1
Our units have the IBM PCI-PCI bridge chips. The DEC bridge chips
(they are used in Adaptec 3940) work fine too.
* You should expect FreeBSD to work with all bug-free
* PCI chip sets. All current Intel chip sets work just
* fine, and I think SiS is generally OK, too. There
* have been problems with Compaq and ALI chip sets,
* but workarounds are implemented to compensate for
* their bugs ...
Note that it also depends on the BIOS if you want to use deep bridging
like the above. At the time we tested (1 1/2 years ago), at least
Award BIOS didn't support more than one level of bridges (so we could
use 3940's but not the expansion boxes). This may have changed.
* Let me know, if you have any problems with some chip
* set and I'll send debug patches and will try to find
* a fix as soon as possible.
Yeah, he's very good at that. I can vouch for him. :)
Satoshi
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