Hi, amdgpu + IOMMU + SME is now working for me on 5.7, yay! But, it is broken on torvalds master, boo. On boot, depending on which exact commit I test, it either hangs immediately (with built-in driver, before starting initramfs), displays some errors then hangs, or spams the screen with many amdgpu errors. I bisected the black screen hang to: commit dce8d6964ebdb333383bacf5e7ab8c27df151218 Author: Joerg Roedel <jroedel@xxxxxxx> Date: Wed Apr 29 15:36:53 2020 +0200 iommu/amd: Convert to probe/release_device() call-backs Convert the AMD IOMMU Driver to use the probe_device() and release_device() call-backs of iommu_ops, so that the iommu core code does the group and sysfs setup. Signed-off-by: Joerg Roedel <jroedel@xxxxxxx> Link: https://lore.kernel.org/r/20200429133712.31431-16-joro@xxxxxxxxxx Signed-off-by: Joerg Roedel <jroedel@xxxxxxx> Testing torvalds master (623f6dc593) with the containing merge (98bdc74b36) plus the DMA mapping merge (4e94d08734) reverted allows amdgpu + IOMMU + SME to once again work. I think that nobody is really working on amdgpu + SME, but it would be a shame if it was supported and then incidentally broken by a small change. I am using an ASRock B450 Pro4 with Ryzen 1600 and ASUS RX 480. I don't understand this code at all, but let me know what I can do to troubleshoot. Thanks, Alex.