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Date: Wed, 18 Feb 2009 18:19:35 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>, David Woodhouse <dwmw2@infradead.org>,
       Stephen Rothwell <sfr@canb.auug.org.au>,
       'iommu@lists.linux-foundation.org', LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Suspend and Resume Support for Intel IOMMU
Message-ID: <20090218171935.GA14625@elte.hu>
References: <20090218165633.GA20167@linux-os.sc.intel.com> <alpine.LFD.2.00.0902180910160.21686@localhost.localdomain>
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* Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Wed, 18 Feb 2009, Fenghua Yu wrote:
> >
> > +static int vtd_enabled;
> ..
> > +static int iommu_resume(struct sys_device *dev)
> > +{
> ..
> > +	if (!vtd_enabled)
> > +		return 0;
> 
> Hmm. Why do this?
> 
> Wouldn't it be much more logical to only register the 
> iommu_sysdev if the thing is enabled, rather than having an 
> odd flag that gets tested at runtime?

The sysdev_class_register() could be done straight in 
intel_iommu_init(), because that gets called by pci_iommu_init() 
which is an fs_initcall() - so all the sysdev facilities should 
be up and running already.

	Ingo