reduced braking when not absolutely needed

selfdrive/car/volkswagen/carcontroller.py

@@ -66,10 +66,11 @@ class CarController():
 
         cb_pos = 0.0 if lead_visible or CS.out.vEgo < 2.0 else 0.1  # react faster to lead cars, also don't get hung up at DSG clutch release/kiss points when creeping to stop
         cb_neg = 0.0 if accel < 0 else 0.2  # IDK why, but stock likes to zero this out when accel is negative
+        secondary_accel = accel if lead_visible else 0  # try matching part of stock behavior, presumably drag/compression brake only if we can get away with it
 
         idx = (frame / P.ACC_CONTROL_STEP) % 16
         can_sends.append(volkswagencan.create_mqb_acc_06_control(self.packer_pt, CANBUS.pt, enabled, acc_status,
-                                                                 accel, self.acc_stopping, self.acc_starting,
+                                                                 accel, secondary_accel, self.acc_stopping, self.acc_starting,
                                                                  cb_pos, cb_neg, idx))
         can_sends.append(volkswagencan.create_mqb_acc_07_control(self.packer_pt, CANBUS.pt, enabled,
                                                                  accel, acc_hold_request, acc_hold_release,

selfdrive/car/volkswagen/volkswagencan.py

@@ -85,7 +85,7 @@ def create_mqb_acc_06_control(packer, bus, enabled, acc_status, accel, acc_stopp
 
   return packer.make_can_msg("ACC_06", bus, values, idx)
 
-def create_mqb_acc_07_control(packer, bus, enabled, accel, acc_hold_request, acc_hold_release,
+def create_mqb_acc_07_control(packer, bus, enabled, accel, secondary_accel, acc_hold_request, acc_hold_release,
                               acc_hold_type, stopping_distance, idx):
   values = {
     "ACC_Distance_to_Stop": stopping_distance,
@@ -93,7 +93,7 @@ def create_mqb_acc_07_control(packer, bus, enabled, accel, acc_hold_request, acc
     "ACC_Freewheel_Type": 2 if enabled else 0,
     "ACC_Hold_Type": acc_hold_type,
     "ACC_Hold_Release": acc_hold_release,
-    "ACC_Accel_Secondary": accel+0.01 if enabled else 3.03,
+    "ACC_Accel_Secondary": secondary_accel+0.01 if enabled else 3.03,  # FIXME: think there are rounding/scaling issues here
     "ACC_Accel_TSK": accel if enabled else 3.01,
   }