Changing these two options also helps on new kernels. So, I have a viable solution to my problem, but leave the bug open, as the failure mode is quite mysterious. Please add quirks so that IOMMU is not used on either of the boards, and that MID does not accept too-big preallocated buffers (even though SUSE had 1024 as the default for a long time - now we have a situation where this leads to bugs).
Changing these two options also helps on new kernels. So, I have a viable solution to my problem, but leave the bug open, as the failure mode is quite mysterious. Please add quirks so that IOMMU is not used on either of the boards, and that MID does not accept too-big preallocated buffers (even though SUSE had 1024 as the default for a long time - now we have a situation where this leads to bugs).