Thank you for all your help! On Tue, Apr 23, 2024 at 1:33 AM Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > > The other way I think is something like this: > > - If it does not have "usb4-host-interface" property (or behind a port > that has that). These are all tunneled (e.g virtual). > > - It is directly connected to a PCIe root port with > "ExternalFacingPort" and it has sibling device that is "Thunderbolt > NHI". This is because you can only have "NHI" on a host router > according to the USB4 spec. > I did find one example of a docking station that uses the DSL6540 chip, which has PCI IDs defined in include/linux/pci_ids.h: #define PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_4C_NHI 0x1577 #define PCI_DEVICE_ID_INTEL_ALPINE_RIDGE_4C_BRIDGE 0x1578 It seems like it has an NHI, despite being in an external, removable docking station. This appears to contradict what you say about only having "NHI" on a host router. I am assuming that by host router, you mean the fixed discrete, fixed thunderbolt chip, or the thunderbolt controller upstream to the root port. Please correct me if I got anything wrong! Looking at 18-241_ThunderboltController_Brief_HI.pdf, it seems like these Alpine Ridge chips can be used either on a computer or a peripheral. (Expected usage: Computer or peripheral) So I'm not sure if finding an NHI would guarantee that the device is not a peripheral. My original question was how to distinguish a Thunderbolt controller that is on a removable peripheral, like a docking station-- from one that is a discrete chip fixed to a computer or upstream to the root port. So unless I am misunderstanding something, it appears that my only option is waiting for Lukas's patches. Please correct me if that is not the case!
