linux-kernel - Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.

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Date:	Mon, 07 Jan 2008 23:59:33 +0100
From:	Rene Herman <rene.herman@...access.nl>
To:	Bodo Eggert <7eggert@....de>
CC:	"H. Peter Anvin" <hpa@...or.com>,
	Christer Weinigel <christer@...nigel.se>,
	Ingo Molnar <mingo@...e.hu>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	"David P. Reed" <dpreed@...d.com>,
	Rene Herman <rene.herman@...il.com>,
	Paul Rolland <rol@...917.net>, Pavel Machek <pavel@....cz>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
	rol@...be.net
Subject: Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.

On 07-01-08 23:27, Bodo Eggert wrote:

> On Mon, 7 Jan 2008, H. Peter Anvin wrote:

>> There might have been a few 386/20's clocking the ISA bus at ÷3 (6.67
>> MHz) rather than ÷2 (10 MHz) or ÷2.5 (8 MHz).
> 
> Yes, and the remaining users should set the kernel option. Both of them. 
> The question is: How will they be told about the new kernel option?

What exactly are you guys still talking about? Alan is looking at drivers 
and finds that in them outb_p is generally correct and correctly specified 
in bus-clocks for at least some (8390 was quoted). In those legacy drivers, 
the _p ops can simply stay and can use the 15-year old proven 0x80 outb.

(with molnar suggesting they be renamed isa_in/outb_p and me suggesting that 
if someone would be doing _that_ they might as well split them manually in 
outb(); slow_down_io() possibly renaming slow_down_io() to isa_io_delay() or 
similar).

Is this only about the ones then left for things like legacy PIC and PIT? 
Does anyone care about just sticking in a udelay(2) (or 1) there as a 
replacement and call it a day?

Rene.

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