Comment # 47 on bug 1202492 from Takashi Iwai

Thanks!  The stack trace is intentional to show the call site.

The log indicates that the code path changing the group->domain is:
  amdgpu_pci_probe ->
  amdgpu_driver_load_kms ->
  amdgpu_device_init ->
  amdgpu_amdkfd_device_init ->
  kgd2kfd_device_init ->
  kgd2kfd_resume_iommu ->
  kfd_iommu_resume ->
  amd_iommu_init_device ->
  iommu_attach_group ->
  __iommu_attach_group

that happens during AMDGPU driver probe.  Afterwards, snd-hda-intel driver gets
probed, but it fails because those audio PCI devices belong  to the same IOMMU
group as the AMD graphics PCI device, and the group->domain is no longer equal
with group->default_domain.