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Re: [PATCH] I/O helpers rework

To: Atsushi Nemoto <>
Subject: Re: [PATCH] I/O helpers rework
From: "Maciej W. Rozycki" <>
Date: Mon, 10 Jan 2005 18:11:14 +0000 (GMT)
In-reply-to: <>
Original-recipient: rfc822;
References: <> <> <> <>
On Tue, 11 Jan 2005, Atsushi Nemoto wrote:

> Well, maybe the 'volatile' have no sense, but some archs (including
> i386, of course :-)) and some drivers use it.  Adding the 'volatile'
> will remove some compiler warnings.

 As will removing "volatile" from broken ports.

> Yes, virt-to-phys conversion might be needed, but if we only use KSEG1
> for I/O port/memory, it does not matter.

 ioremap() is free to return a KSEG2 address on a 32-bit system.  With 
64-bit systems there is no problem.

> And I have some custom boards which really needs different swapping
> properties (PCI regions need SWAP_IO_SPACE, but ISA region does not,
> for example).  I agree that those boards were misdesigned but I want
> to run Linux on it without modifying existing drivers.

 Hmm, that's strange -- does the system glue ISA otherwise than behind a 
PCI-ISA bridge?  So far I've only spotted a single PCI/ISA system wiring 
the buses as "peers", namely the ancient Intel's i82420EX for 486-class 


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