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Date:   Thu, 6 Oct 2022 15:01:14 +0100
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Subject: Re: [PATCH v4 05/16] iommu: Move bus setup to IOMMU device
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To:     Robin Murphy <robin.murphy@arm.com>, joro@8bytes.org
Cc:     will@kernel.org, iommu@lists.linux.dev,
        linux-arm-kernel@lists.infradead.org, baolu.lu@linux.intel.com,
        kevin.tian@intel.com, suravee.suthikulpanit@amd.com,
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        "linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
        Thierry Reding <treding@nvidia.com>
References: <cover.1660572783.git.robin.murphy@arm.com>
 <d342b6f27efb5ef3e93aacaa3012d25386d74866.1660572783.git.robin.murphy@arm.com>
From:   Jon Hunter <jonathanh@nvidia.com>
In-Reply-To: <d342b6f27efb5ef3e93aacaa3012d25386d74866.1660572783.git.robin.murphy@arm.com>
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Hi Robin,

On 15/08/2022 17:20, Robin Murphy wrote:
> Move the bus setup to iommu_device_register(). This should allow
> bus_iommu_probe() to be correctly replayed for multiple IOMMU instances,
> and leaves bus_set_iommu() as a glorified no-op to be cleaned up next.
> 
> At this point we can also handle cleanup better than just rolling back
> the most-recently-touched bus upon failure - which may release devices
> owned by other already-registered instances, and still leave devices on
> other buses with dangling pointers to the failed instance. Now it's easy
> to clean up the exact footprint of a given instance, no more, no less.


Since this change, I have noticed that the DRM driver on Tegra20 is 
failing to probe and I am seeing ...

  tegra-gr2d 54140000.gr2d: failed to attach to domain: -19
  drm drm: failed to initialize 54140000.gr2d: -19

Bisect points to this change and reverting it fixes it. Let me know if 
you have any thoughts.

Cheers
Jon

-- 
nvpublic