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To: Ingo Molnar <mingo@elte.hu>
Cc: Pavel Machek <pavel@ucw.cz>, kernel list <linux-kernel@vger.kernel.org>,
       Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: iommu: it could use some documentation
References: <20080319145811.GA27113@elf.ucw.cz>
	<20080319151346.GA28798@elte.hu>
From: Andi Kleen <andi@firstfloor.org>
Date: 21 Mar 2008 16:55:51 +0100
In-Reply-To: <20080319151346.GA28798@elte.hu>
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Ingo Molnar <mingo@elte.hu> writes:
> 
> > +	iommu=		[x86]
> > +		off
> > +		force
> > +		noforce
> > +		biomerge
> > +		panic
> > +		nopanic
> > +		merge
> > +		nomerge
> > +		forcesac
> > +		soft
> 
> these are mostly quirks to get boards booting

Actually no. Except perhaps for iommu=soft none of them is related
to any  hardware issues. They all tune various performance trade offs
and were supplied for performance tuning originally.

-Andi