Hello Robin, Hope you are doing well. I am Chaitanya from the linux graphics team in Intel. This mail is regarding a regression we are seeing in our CI runs[1] on linux-next repository. Since the version next-20250312 [2], we are seeing the following regression ````````````````````````````````````````````````````````````````````````````````` <4>[ 6.246790] reg-dummy reg-dummy: late IOMMU probe at driver bind, something fishy here! <4>[ 6.246812] WARNING: CPU: 0 PID: 1 at drivers/iommu/iommu.c:449 __iommu_probe_device+0x140/0x570 <4>[ 6.246822] Modules linked in: <4>[ 6.246830] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.14.0-rc6-next-20250312-next-20250312-g9fbcd7b32bf7+ #1 <4>[ 6.246838] Hardware name: Intel Corporation Arrow Lake Client Platform/MTL-S UDIMM 2DPC EVCRB, BIOS MTLSFWI1.R00.4400.D85.2410100007 10/10/2024 <4>[ 6.246847] RIP: 0010:__iommu_probe_device+0x140/0x570 ````````````````````````````````````````````````````````````````````````````````` Details log can be found in [3]. After bisecting the tree, the following patch [4] seems to be the first "bad" commit ````````````````````````````````````````````````````````````````````````````````````````````````````````` commit bcb81ac6ae3c2ef95b44e7b54c3c9522364a245c Author: Robin Murphy mailto:robin.murphy@xxxxxxx Date: Fri Feb 28 15:46:33 2025 +0000 iommu: Get DT/ACPI parsing into the proper probe path ````````````````````````````````````````````````````````````````````````````````````````````````````````` We also verified that if we revert the patch the issue is not seen. Could you please check why the patch causes this regression and provide a fix if necessary? Thank you. Regards Chaitanya [1] https://intel-gfx-ci.01.org/tree/linux-next/combined-alt.html? [2] https://web.git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20250312 [3] https://intel-gfx-ci.01.org/tree/linux-next/next-20250312/bat-arls-6/boot0.txt [4] https://web.git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20250312&id=bcb81ac6ae3c2ef95b44e7b54c3c9522364a245c
