[PATCH rc] gpu: host1x: Do not assume that a NULL domain means no DMA IOMMU

[Diogo Ivo]

Hello again,

On 2/4/25 7:18 PM, Jason Gunthorpe wrote:
> Previously with tegra-smmu, even with CONFIG_IOMMU_DMA, the default domain
> could have been left as NULL. The NULL domain is specially recognized by
> host1x_iommu_attach() as meaning it is not the DMA domain and
> should be replaced with the special shared domain.
> 
> This happened prior to the below commit because tegra-smmu was using the
> NULL domain to mean IDENTITY.
> 
> Now that the domain is properly labled the test in DRM doesn't see NULL.
> Check for IDENTITY as well to enable the special domains.
> 
> This is the same issue and basic fix as seen in
> commit fae6e669cdc5 ("drm/tegra: Do not assume that a NULL domain means no
> DMA IOMMU").
> 
> Fixes: c8cc2655cc6c ("iommu/tegra-smmu: Implement an IDENTITY domain")
> Reported-by: Diogo Ivo <diogo.ivo at tecnico.ulisboa.pt>
> Closes: https://lore.kernel.org/all/c6a6f114-3acd-4d56-a13b-b88978e927dc@tecnico.ulisboa.pt/
> Tested-by: Diogo Ivo <diogo.ivo at tecnico.ulisboa.pt>
> Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>

Any news on this patch or any other solutions for this regression? It's
not great if this falls through the cracks, especially when there is a
solution for the problem.

Thanks,
Diogo