Date: Fri, 24 Mar 2006 05:23:39 +0200
From: Muli Ben-Yehuda <mulix@mulix.org>
Subject: Re: [PATCH 3/3] x86-64: Calgary IOMMU - hook it in
In-reply-to: <200603231736.44223.ak@suse.de>
To: Andi Kleen <ak@suse.de>
Cc: Jon Mason <jdmason@us.ibm.com>, Muli Ben-Yehuda <muli@il.ibm.com>,
       Linux-Kernel <linux-kernel@vger.kernel.org>, discuss@x86-64.org,
       Andrew Morton <akpm@osdl.org>
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On Thu, Mar 23, 2006 at 05:36:43PM +0100, Andi Kleen wrote:

> > +static int __init pci_iommu_init(void)
> > +{
> > +	int rc = 0;
> > +
> > +#ifdef CONFIG_GART_IOMMU
> > +	rc = gart_iommu_init();
> > +	if (!rc) /* success? */
> > +		return 0;
> > +#endif
> > +#ifdef CONFIG_CALGARY_IOMMU
> > +	rc = calgary_iommu_init();
> > +#endif
> 
> This is weird. Normally I would expect you to detect the calgary thing first
> and only then run the gart_iommu detection if not found. Why this
> order?

Seniority? :-) these are mutually exclusive, really, so we didn't
consider it important which runs "first".

> Fixing that would also not require adding the additional hacks to gart iommu
> you added.

We'll still need it at least to stop swiotlb from kicking in in
pci_swiotlb_init if we detected either gart or Calgary.

Cheers,
Muli
-- 
Muli Ben-Yehuda
http://www.mulix.org | http://mulix.livejournal.com/

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