Created attachment 142968 [details]
dmesg output with without iommu_intel set
iommu_intel=on fails with i915 on x201 Thinkpad.
Thread on LKML: https://lore.kernel.org/lkml/20181227114948.ev4b3jte3ubsc5us@dcvr/T/
Created attachment 142969 [details]
dmesg output with iommu_on
Created attachment 142970 [details]
Debian 4.17 config
My apologies for responding on this issue so late.
@Joonas, any suggestion how to proceed with this issue?