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Since commit 57365a04c921 ("iommu: Move bus setup > > > > The iommu_present() is only used in below two drivers. > > > > $ git grep iommu_present > > drivers/gpu/drm/mediatek/mtk_drm_drv.c: if > > (!iommu_present(&platform_bus_type)) > > drivers/gpu/drm/tegra/drm.c:    if (host1x_drm_wants_iommu(dev) && > > iommu_present(&platform_bus_type)) { > > > > Both are platform drivers and have the device pointer passed in. Just > > out of curiosity, why not replacing them with device_iommu_mapped() > > instead? Sorry if I overlooked previous discussion. > > Yes, we've already gone round in circles on this several times, that's why > it's explicitly called out as "stubbornly difficult" in the commit message. > The Mediatek one is entirely redundant, but it seems I have yet to figure > out the right CC list to get anyone to care about that patch[1]. Please just have Joerg take such a trivial patch, there is no reason we need to torture outselves because DRM side is not behaving well. :( Jason