PCI and USB bus standards include dynamic enumeration but ARM SOCs normally only use them as external interfaces.
IP blocks inside the SOC itself usually just expose their registers on an AXI bus with no enumeration support at all, this is most likely the case with the M1 gpu.
IP blocks inside the SOC itself usually just expose their registers on an AXI bus with no enumeration support at all, this is most likely the case with the M1 gpu.