The acpiwmibus interface attribute should be handled by combining the definition in files.wmi with the logic in wmi_acpi.c to call config_found:
# ACPI WMI mapper device acpiwmi: acpiwmibus attach acpiwmi at acpinodebus file dev/acpi/wmi/wmi_acpi.c acpiwmi /* acpi_wmi_attach */ acpi_wmi_rescan(self, NULL, NULL); /* acpi_wmi_rescan */ if (sc->sc_child == NULL) { sc->sc_child = config_found(self, NULL, acpi_wmi_print, CFARGS_NONE); } It's very confusing, though, that this automagically figures out to use "acpiwmibus" even though it's not named to config_found -- makes it hard to search for. The name "acpiwmibus" ought to be be written in the source code to make this more obvious and less magic. I feel we should really make it an error (or at least a warning) if config_found is used with no explicit interface attribute to find children via an interface attribute. I think it used to be that way when we had config_found_ia; this appears to be a something of a regression in the API. Do you have the wmi guid in dmesg with `boot -x' (debug)? Does it match any guid in any of the wmi drivers? => If yes, that would indicate something is going wrong here. => If no, that suggests we just don't have a driver for your wmi.