ACS override patch to isolate target device from IOMMU group

Hi, I encountered an issue while playing around Jetson Xavier NX development kit. My board is flashed through the standard process instructed in Getting Started With Jetson Xavier NX Developer Kit | NVIDIA Developer

I am trying to isolate the target device of id 10ec:c822 in the following image so that I can perform PCI passthrough to qemu vm. (both devices are within the same IOMMU group).

To my knowledge, the other device of id 10de:1ad1, which is PCI bridge, is not supported by the vfio-pci driver, hence it is not able to be bound to vfio-pci driver, but only required to be unbound from the standard driver. After binding the target device to vfio-pci driver and unbinding the PCI bridge, qemu still generates the following error.

I am wondering if the (dummy ?) device of name ‘14160000.pcie’ is the root cause of this problem.

To walk around this issue, I applied the ACS override patch to isolate the target device from IOMMU goup 6. As shown in the kernel message, the functions in the override patch note is indeed called, however, the IOMMU group remains the same.

is there anyway I can isolate the target device so that I can perform pcie passthrough?