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Date: Sat, 16 Jun 2001 11:15:04 -0700 (PDT)
From: Linus Torvalds <torvalds@transmeta.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
cc: Jeff Garzik <jgarzik@mandrakesoft.com>, Eric Smith <eric@brouhaha.com>,
        linux-kernel@vger.kernel.org, arjanv@redhat.com, mj@ucw.cz
Subject: Re: 2.4.2 yenta_socket problems on ThinkPad 240
In-Reply-To: <E15BKPA-0008O7-00@the-village.bc.nu>
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On Sat, 16 Jun 2001, Alan Cox wrote:
>
> > core should be more than just the kissing cousins they are now.  OTOH I
> > still don't like how much we trust firmware PCI bus setup on x86..
> 
> The BIOS may make assumptions we dont know about such as the bus layout. What
> minimises the problem is effectively to validate the firmware provided PCI
> setup and if its crap, then do the job ourselves. That minimizes the problems
> 
> Hence I think it should not be a define but an __init validator for the bus
> setup

Yes.

Regardless, it would certainly make sense to have a manual override, with
a kernel command line. If for no other reason than to allow for mistakes
and let the user force the old/new behaviour.

So the #define should be a variable with a kernel command line override,
along with a heuristic for the kernel to do a good guess on its own (and
the heuristic should probably not be as global as the current
"pcibios_assign_all_busses()" test - the heuristic will be able to tell on
a bridge basis on whether that bridge may need assignment. This might
imply giving the "pcibios_assign_all_busses()" thing the "dev" as an
argument).

		Linus