init

common/params_keys.h

@@ -16,6 +16,8 @@ inline static std::unordered_map<std::string, ParamKeyAttributes> keys = {
     {"AthenadUploadQueue", {PERSISTENT, JSON}},
     {"AthenadRecentlyViewedRoutes", {PERSISTENT, STRING}},
     {"BootCount", {PERSISTENT, INT}},
+    {"BusDetectionChanged", {CLEAR_ON_MANAGER_START | CLEAR_ON_ONROAD_TRANSITION, BOOL}},
+    {"BusDetectionEnabled", {CLEAR_ON_MANAGER_START | CLEAR_ON_ONROAD_TRANSITION, BOOL}},
     {"CalibrationParams", {PERSISTENT, BYTES}},
     {"CameraDebugExpGain", {CLEAR_ON_MANAGER_START, STRING}},
     {"CameraDebugExpTime", {CLEAR_ON_MANAGER_START, STRING}},

selfdrive/car/card.py

@@ -15,7 +15,7 @@ from opendbc.car import DT_CTRL, structs
 from opendbc.car.can_definitions import CanData, CanRecvCallable, CanSendCallable
 from opendbc.car.carlog import carlog
 from opendbc.car.fw_versions import ObdCallback
-from opendbc.car.car_helpers import get_car, interfaces
+from opendbc.car.car_helpers import get_car, interfaces, BusDetectionCallback
 from opendbc.car.interfaces import CarInterfaceBase, RadarInterfaceBase
 from openpilot.selfdrive.pandad import can_capnp_to_list, can_list_to_can_capnp
 from openpilot.selfdrive.car.cruise import VCruiseHelper
@@ -39,6 +39,17 @@ def obd_callback(params: Params) -> ObdCallback:
   return set_obd_multiplexing
 
 
+def bus_detection_callback(params: Params) -> BusDetectionCallback:
+  def set_bus_detection(enabled: bool):
+    if params.get_bool("BusDetectionEnabled") != enabled:
+      cloudlog.warning(f"Setting bus detection mode to {enabled}")
+      params.remove("BusDetectionChanged")
+      params.put_bool("BusDetectionEnabled", enabled)
+      params.get_bool("BusDetectionChanged", block=True)
+      cloudlog.warning("Bus detection mode set successfully")
+  return set_bus_detection
+
+
 def can_comm_callbacks(logcan: messaging.SubSocket, sendcan: messaging.PubSocket) -> tuple[CanRecvCallable, CanSendCallable]:
   def can_recv(wait_for_one: bool = False) -> list[list[CanData]]:
     """
@@ -97,7 +108,8 @@ class Car:
         with car.CarParams.from_bytes(cached_params_raw) as _cached_params:
           cached_params = _cached_params
 
-      self.CI = get_car(*self.can_callbacks, obd_callback(self.params), alpha_long_allowed, is_release, cached_params)
+      self.CI = get_car(*self.can_callbacks, obd_callback(self.params), alpha_long_allowed, is_release, cached_params,
+                        set_bus_detection=bus_detection_callback(self.params))
       self.RI = interfaces[self.CI.CP.carFingerprint].RadarInterface(self.CI.CP)
       self.CP = self.CI.CP
 

selfdrive/pandad/panda_safety.cc

@@ -35,6 +35,18 @@ void PandaSafety::updateMultiplexingMode() {
     prev_obd_multiplexing_ = obd_multiplexing_requested;
     params_.putBool("ObdMultiplexingChanged", true);
   }
+
+  // Switch to noOutput passthrough for bus detection (relay engaged, forwarding enabled, no TX)
+  bool bus_detection_requested = params_.getBool("BusDetectionEnabled");
+  if (bus_detection_requested != prev_bus_detection_) {
+    if (bus_detection_requested) {
+      panda_->set_safety_model(cereal::CarParams::SafetyModel::NO_OUTPUT_PASSTHROUGH);
+    } else {
+      panda_->set_safety_model(cereal::CarParams::SafetyModel::ELM327, 1U);
+    }
+    prev_bus_detection_ = bus_detection_requested;
+    params_.putBool("BusDetectionChanged", true);
+  }
 }
 
 std::string PandaSafety::fetchCarParams() {

selfdrive/pandad/pandad.h

@@ -21,6 +21,7 @@ private:
   bool log_once_ = false;
   bool safety_configured_ = false;
   bool prev_obd_multiplexing_ = false;
+  bool prev_bus_detection_ = false;
   Panda *panda_;
   Params params_;
 };