On the system where I have installed the 4.15.xxx kernel and usbip from Debian/sid, I get the following results from "usbip --debug port":
[...] usbip: debug: names.c:428:[parse] line 18068 subclass fe:02 IRDA Bridge usbip: debug: names.c:428:[parse] line 18069 subclass fe:03 Test and Measurement usbip: debug: names.c:461:[parse] line 18070 protocol fe:03:01 TMC usbip: debug: names.c:461:[parse] line 18071 protocol fe:03:02 USB488 usbip: debug: names.c:374:[parse] line 18072 class ff Vendor Specific Class usbip: debug: names.c:428:[parse] line 18073 subclass ff:ff Vendor Specific Subclass usbip: debug: names.c:461:[parse] line 18074 protocol ff:ff:ff Vendor Specific Protocol libusbip: debug: vhci_driver.c:264:[usbip_vhci_driver_open] available ports: 240 libusbip: error: port number exceeds 128 usbip: error: open vhci_driver usbip: error: list imported devices The line where the condition is checked is https://elixir.bootlin.com/linux/v4.15.4/source/tools/usb/usbip/libsrc/vhci_driver.c#L263 vhci_driver <https://elixir.bootlin.com/linux/v4.15.4/ident/vhci_driver>->nports = get_nports <https://elixir.bootlin.com/linux/v4.15.4/ident/get_nports>(); dbg <https://elixir.bootlin.com/linux/v4.15.4/ident/dbg>("available ports: %d", vhci_driver <https://elixir.bootlin.com/linux/v4.15.4/ident/vhci_driver>->nports); if (vhci_driver <https://elixir.bootlin.com/linux/v4.15.4/ident/vhci_driver>->nports <= 0) { err("no available ports"); goto err; } else if (vhci_driver <https://elixir.bootlin.com/linux/v4.15.4/ident/vhci_driver>->nports > MAXNPORT <https://elixir.bootlin.com/linux/v4.15.4/ident/MAXNPORT>) { err("port number exceeds %d", MAXNPORT <https://elixir.bootlin.com/linux/v4.15.4/ident/MAXNPORT>); goto err; } Maybe the viable workaround would be just to increase the MAXNPORT number? -- Wojciech M Zabolotny, PhD Institute of Electronic Systems Faculty of Electronics and Information Technology Warsaw University of Technology