Date: Mon, 29 Jun 2015 15:16:56 +0200
From: Joerg Roedel <jroedel@suse.de>
To: Eric Auger <eric.auger@linaro.org>
Cc: Will Deacon <Will.Deacon@arm.com>,
        Baptiste Reynal <b.reynal@virtualopensystems.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: Regression observed since "iommu: Propagate error in
 add_iommu_group" with arm-smmu
Message-ID: <20150629131656.GB16648@suse.de>
References: <55913E36.4010407@linaro.org>
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Hi Eric

On Mon, Jun 29, 2015 at 02:46:46PM +0200, Eric Auger wrote:
> Hi Joerg, Will
> 
> I observe a regression since commit
> 19762d7095e6392b6ec56c363a6f29b2119488c2 (iommu: Propagate error in
> add_iommu_group) with arm-smmu: I am not able to bind the vfio-platform
> driver to one Calxeda Midway xgmac anymore. This latter is not assigned
> any group.
> 
> Looks like the cause is, in iommu_bus_init, when doing
> bus_for_each_dev(bus, NULL, &cb, add_iommu_group),
> add_iommu_group fails for some devices which are not upstream to smmu
> and enumerated before the xgmac. As a consequence  bus_for_each_dev
> returns without looking at the xgmac.
> 
> arm_smmu_add_platform_device currently returns -ENODEV when no smmu/no
> master port for the device. Shouldn't we return 0 now?

I posted a patch today which fixes this by ignoring -ENODEV as a return
value in add_iommu_group. See here:

	http://lists.linuxfoundation.org/pipermail/iommu/2015-June/013508.html

I'll send this fix upstream asap (means: tomorrow). It would be great if
you can test it too in your setup.


	Joerg

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