From owner-freebsd-hackers  Sat Jan 20 20:11:57 2001
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From: Andrew Gallatin <gallatin@cs.duke.edu>
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Date: Sat, 20 Jan 2001 23:11:39 -0500 (EST)
To: Nicolas Souchu <nsouch@alcove.fr>
Cc: freebsd-hackers@freebsd.org
Reply-To: trim-your-headers@loopback.net
Subject: Re: more info about: odd result of pci_read_config
In-Reply-To: <20010121004349.A27198@ontario.alcove-int>
References: <20010120161834.B20753@ontario.alcove-int>
	<20010121004349.A27198@ontario.alcove-int>
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Nicolas Souchu writes:
<...>
 > What is the hose field?

It is for server-class alphas.  Alphas do their peer PCI buses a
little differently.  Rather than have a ppb between "peer" pci buses,
each different peer bus (or hose) is rooted separately at the nexus.
So you can have two PCI buses labeled "0" with no ppb between them,
for example.  Platform support code needs to know which hose a bus is
on so that it can diddle with the correct set of registers to access
memory, i/o and pci config spaces.

 > 	cfg.hose = -1;

If you need to set this, please set it to zero so that it and any code
derived from it will have at least a fighting chance of working on
alpha, where this field is not ignored..

Drew


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