From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joerg Roedel <jroedel-l3A5Bk7waGM@public.gmane.org>
Subject: Re: [PATCH 03/22] iommu: Propagate error in add_iommu_group
Date: Mon, 29 Jun 2015 11:37:03 +0200
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Cc: Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>, djkurtz-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, Tomasz Figa <tfiga-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Kukjin Kim <kgene-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Laurent Pinchart <laurent.pinchart-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>, David Woodhouse <dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
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Hello Heiko,

On Mon, Jun 29, 2015 at 11:28:40AM +0200, Heiko St=FCbner wrote:
> The Rockchip iommu uses bus_set_ops to set its iommu-ops for the platform
> bus and currently returns -ENODEV if it encounters a platform_devices that
> does not have an iommu. As add_iommu_group ignored these returns
> till now this worked, but of course starts to fail now.
> =

> All two invocations of the add_device callback ignored (or still ignore) =
the
> return value so I've come with the following small patch to fix the break=
age
> that now exists in the 4.2 tree.
> =

> There is probably a better solution possible in the longer term, likely
> similar to what Samsung does, but I'm not sure yet how this would work
> with our drm device that needs an iommu mapping without having an
> iommu (the iommus being attached to the crtc-components).

Yes, this issue was already reported from the Exynos side. I have a fix
which just ignores -ENODEV as the return value for now. This fixes
Exynos, and should fix Rockchip (and some other IOMMU drivers) too.


	Joerg