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

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Message-ID: <47781499.5010209@keyaccess.nl>
Date:	Sun, 30 Dec 2007 22:58:49 +0100
From:	Rene Herman <rene.herman@...access.nl>
To:	"H. Peter Anvin" <hpa@...or.com>
CC:	Ingo Molnar <mingo@...e.hu>, Bodo Eggert <7eggert@....de>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	dpreed@...d.com, Islam Amer <pharon@...il.com>,
	Pavel Machek <pavel@....cz>, Ingo Molnar <mingo@...hat.com>,
	Andi Kleen <andi@...stfloor.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override

On 30-12-07 22:44, H. Peter Anvin wrote:
> Ingo Molnar wrote:
>>>>
>>> It probably should actually HLT, to avoid sucking power, and 
>>> stressing the thermal system.  We're dead at this point, and the 
>>> early 486's which had problems with HLT will lock up - we don't care.
>>
>> ok. Like the patch below?
>>
> 
> Don't need the cli; we're already running with interrupts disabled.
> 
> I'd do:
> 
>     while (1)
>         asm volatile("hlt");
> 
> ... mostly on general principles.

At least with current GCC the volatile isn't strictly needed as its implied 
without output operands but I was only certain after checking that. Do you 
remember if that used to be different for previous GCC versions? I tend to 
also stick volatiles on them still...

Rene.
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