"David S. Miller" <davem@redhat.com> writes:
> Date: Tue, 24 Oct 2000 13:50:10 -0700 (PDT)
> From: Linus Torvalds <torvalds@transmeta.com>
>
> Does the above make it work for you? I don't know if PCI even has
> the notion of transparent bridging, and quite frankly I doubt it
> does. The above would be nothing but a hack that basically says "I
> don't understand the resources of this bridge, so I'll just say it
> bridges everything".
>
> I bet PCI allows no such thing, thus to be totally safe I would
> conditionalize this feature on the specific bridge. Ie. only allow
> it for this bridge type, because I bet it is just some bug in the
> the address comparators which makes the bridge interpret zero ranges
> as "forward and respond to everything".
I'm not certain of the details but I do know that it is legal.
To date I've only heard of it on ISA bridges, in particular the PIIXE.
It's some kind of passive listening mode as opposed to actually claiming
the bus cycles.
> This only would make sense if the bridge snooped config space access
> to devices behind it, so that it knew what addresses to forward and
> respond to. Just responding to "everything" would not work for
> obvious reasons.
Right but I don't think you actually have to respond. Not that I think
this is a good idea, but it does appear to be legal.
Eric
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