Using amdgpu as a display offload source is currently not supported due to an incompatibility between how the amdgpu driver creates “transparent huge pages” without the compound page flag set and how the NVIDIA driver tries to map them. You can see that this is happening in the dmesg log:
[ 49.852234] Unhandled error in __nv_drm_gem_user_memory_handle_vma_fault: -22
Unfortunately, the only current workaround is to recompile the kernel without the CONFIG_TRANSPARENT_HUGEPAGE flag enabled. We’re investigating other ways to work around the problem.