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Date:   Tue, 15 Oct 2019 13:40:45 +0200
From:   Joerg Roedel <joro@8bytes.org>
To:     Chris Wilson <chris@chris-wilson.co.uk>
Cc:     iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iommu/intel: Use fallback generic_device_group() for
 ACPI devices
Message-ID: <20191015114045.GJ14518@8bytes.org>
References: <20191004205554.21055-1-chris@chris-wilson.co.uk>
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On Fri, Oct 04, 2019 at 09:55:54PM +0100, Chris Wilson wrote:
> [    2.073922] DMAR: ACPI device "INT33C2:00" under DMAR at fed91000 as 00:15.1
> [    2.073983] DMAR: ACPI device "INT33C3:00" under DMAR at fed91000 as 00:15.2
> [    2.074027] DMAR: ACPI device "INT33C0:00" under DMAR at fed91000 as 00:15.3
> [    2.074072] DMAR: ACPI device "INT33C1:00" under DMAR at fed91000 as 00:15.4

I think just using generic_device_group() is not enough here. You need
to mach the device-id of the ACPI device with the PCI hierarchy and find
the right group there. You can look at the AMD IOMMU drivers
acpihid_device_group() function for some inspiration.

Regards,

	Joerg