24.06.2019 10:04, Christoph Hellwig пишет: > Don't we have a device tree problem here if there is a domain covering > them? I though we should only pick up an IOMMU for a given device > if DT explicitly asked for that? > There is no specific domain that "covering them". The IOMMU domain is allocated dynamically during of the Tegra DRM's driver initialization (see tegra_drm_load) and then all of DRM devices are attached to that domain once all of the DRM sub-drivers are probed successfully. On Tegra SoCs it's up to software (driver) to decide how to separate hardware devices from each other, in a case of DRM we're putting all the relevant graphics devices into a single domain. Is it even possible to express IOMMU domain (not group!) assignments in a device-tree?
