Created attachment 273471 [details] Oops with kernel 4.14.11 Starting with kernel 4.14, there is no display output on the Acer Chromebook 14. I get a KERNEL BUG at exynos-iommu.c:743, exynos_iommu_domain_alloc (even though this device has a Nvidia Tegra K1) Reverting commit 928055a01b3: "iommu/exynos: Remove custom platform device registration code" makes it work again. I have the Oops message and system logs for a working and a failing kernel (the failing one is with kernel 4.14.10 because new versions came out while bisecting, but the bug still exists with the last version)
Created attachment 273473 [details] System log for a failing kernel
Created attachment 273475 [details] System log for a working kernel when it works, i get lots of "iommu: Adding device *name* to group *number*"
FYI, there are few patches pending to disable arm implicit iommu conflicting with iommu handled by tegra: https://github.com/grate-driver/linux/commit/7f0750065a31ae491278a8960c1aceb4a44b847f (see also the others for tegra devices on the grate-driver/linux tree) Hopefully this can be fixed by 4.20
This has been fixed for some time (at least a year)