linux-kernel - Re: [PATCH] x86_64: fix problems due to use of "outb" to port 80 on some AMD64x2 laptops, etc.

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Message-ID: <20071214232955.545ab809@the-village.bc.nu>
Date:	Fri, 14 Dec 2007 23:29:55 +0000
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Pavel Machek <pavel@....cz>, Ingo Molnar <mingo@...e.hu>,
	"David P. Reed" <dpreed@...d.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
	Rene Herman <rene.herman@...access.nl>
Subject: Re: [PATCH] x86_64: fix problems due to use of "outb" to port 80 on
 some AMD64x2 laptops, etc.

On Fri, 14 Dec 2007 14:13:46 -0800
"H. Peter Anvin" <hpa@...or.com> wrote:

> Pavel Machek wrote:
> > On Fri 2007-12-14 10:02:57, H. Peter Anvin wrote:
> >> Ingo Molnar wrote:
> >>> wow, cool fix! (I remember that there were other systems as well that are 
> >>> affected by port 0x80 muckery - i thought we had removed port 0x80 
> >>> accesses long ago.)
> >>> how about the simpler fix below, as a first-level approach? We can then 
> >>> remove the _p in/out sequences after this.
> >> I believe this will suffer from the issue that was raised: this will use 
> >> udelay() long before loop calibration (and no, we can't just "be 
> >> conservative" since there is no "conservative" value we can use.)
> > 
> > ?? Just initialize bogomips to 6GHz equivalent... and we are fine
> > until 6GHz cpus come out.
> 
> How long will that take to boot on a 386?

Well the dumb approach to fix that would seem to be to initialise it to

	cpu->family   3 -> 50MHz 4 -> 300Mhz 5-> etc...

Alan
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