Subject: Multiple busses of the same kind
To: None <,>
From: Aymeric Vincent <>
List: tech-kern
Date: 07/29/2001 22:24:25
[ this e-mail is crossposted to tech-kern and port-i386 ]


A friend of mine filed PR 13557 and I think it gives a pretty
interesting problem to solve.

The problem is basically that the ISA bus is attached twice because he
has two pcib's: one in his laptop, the other provided by his base

As stated in the PR, preventing the second pcib from attaching the ISA
bus made the trick and he could boot properly.

However, I believe it would be nice to have a isa_match_hook() called
by isamatch() which could prevent attachment as soon as one isa bus
has been seen on the i386 arch.

I don't feel confident enough to do the change myself, and such a
change would mean adding a isa_match_hook() to every architecture that
has ISA busses.

Obviously such a restriction (enforcing only one isa bus) can not go
into the MI isa code since I don't see any conceptual reason to
prevent multiple isa busses from coexisting in address space or

Could anyone with enough knowledge please have a look at this PR? I'd
like to see a fix for this in the next 1.5.* branch...