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Re: [PATCH] enable PCI bridges in MIPS ip32

To: Ralf Baechle <>
Subject: Re: [PATCH] enable PCI bridges in MIPS ip32
From: "Maciej W. Rozycki" <>
Date: Fri, 5 Oct 2007 13:10:33 +0100 (BST)
Cc: Giuseppe Sacco <>,
In-reply-to: <>
Original-recipient: rfc822;
References: <> <> <> <> <>
On Thu, 4 Oct 2007, Ralf Baechle wrote:

> It's documented somewhere in their specs.  Whatever, it ends crashing
> the system so device 31 is hands off.

 OK, found it -- it is the GT-64120A erratum FEr#19 leading to a hang of 
the device; perhaps we should mention it briefly in the source code.

 While the PCI spec says reads from the device #31, function #7 for host 
bridges implementing the recommended special cycle generation mechanism 
have undefined results, this behaviour is certainly "undefined" in a very 
silly way and then, according to the spec, it must not happen for the 
function #0, which is the only one probed by Linux by default for 
single-function devices.


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