From 438d015b7ae04a7a1befaa9e589c0de1e2b655e8 Mon Sep 17 00:00:00 2001
From: firestar5683 <168790843+firestar5683@users.noreply.github.com>
Date: Mon, 9 Nov 2026 16:28:34 -0600
Subject: [PATCH] Preserve GM stop-and-go authority at zero minimum speed

---
 openpilot/selfdrive/car/car_events.py         |  3 +-
 .../aol/tests/test_gm_zero_engage_minimum.py  | 81 +++++++++++++++++++
 prebuilt.json                                 |  2 +-
 3 files changed, 84 insertions(+), 2 deletions(-)
 create mode 100644 openpilot/starpilot/aol/tests/test_gm_zero_engage_minimum.py

diff --git a/openpilot/selfdrive/car/car_events.py b/openpilot/selfdrive/car/car_events.py
index 35ffe7c631..0605b2bb7f 100644
--- a/openpilot/selfdrive/car/car_events.py
+++ b/openpilot/selfdrive/car/car_events.py
@@ -85,7 +85,8 @@ class CarEvents:
           events.add(EventName.buttonEnable)
       # Enabling at a standstill with brake is allowed
       # TODO: verify 17 Volt can enable for the first time at a stop and allow for all GMs
-      if CS.vEgo < self.CP.minEnableSpeed and not (CS.standstill and CS.brakePressed and
+      # Zero permits standstill, including a filtered-speed undershoot below zero.
+      if self.CP.minEnableSpeed > 0. and CS.vEgo < self.CP.minEnableSpeed and not (CS.standstill and CS.brakePressed and
                                                    self.CP.networkLocation == NetworkLocation.fwdCamera):
         events.add(EventName.belowEngageSpeed)
       if CS.cruiseState.standstill:
diff --git a/openpilot/starpilot/aol/tests/test_gm_zero_engage_minimum.py b/openpilot/starpilot/aol/tests/test_gm_zero_engage_minimum.py
new file mode 100644
index 0000000000..b8cfb760aa
--- /dev/null
+++ b/openpilot/starpilot/aol/tests/test_gm_zero_engage_minimum.py
@@ -0,0 +1,81 @@
+"""A zero cruise engagement floor must retain stop-and-go authority."""
+from contextlib import ExitStack
+
+import pytest
+from opendbc.car import structs
+from opendbc.car.gm.tests.test_ordinary_camera import params
+from opendbc.car.gm.values import CAR, GMFlags
+from openpilot.common.prefix import OpenpilotPrefix
+from openpilot.selfdrive.car.car_events import CarEvents, EventName
+from openpilot.starpilot.aol.intent import read_settings
+from openpilot.starpilot.aol.tests import test_ioniq_availability as fixture
+
+
+def truck_params():
+  cp = params(CAR.CHEVROLET_SILVERADO, alpha=True)
+  cp.flags |= int(GMFlags.HAS_BSM)
+  assert cp.minEnableSpeed == 0 and cp.openpilotLongitudinalControl and not cp.pcmCruise
+  return cp
+
+
+def stopped(speed):
+  cs = fixture.car_state()
+  cs.vEgo, cs.vEgoRaw, cs.standstill = speed, 0., True
+  cs.cruiseState.available = cs.cruiseState.enabled = cs.cruiseState.standstill = True
+  return cs
+
+
+@pytest.mark.parametrize('speed', [-.04, -.00876117, -.0000004, 0., .02])
+def test_zero_minimum_accepts_filtered_standstill_undershoot(speed):
+  cp = truck_params()
+  cs = stopped(speed)
+  events = CarEvents(cp).update(cs, cs, structs.CarControl(enabled=True))
+  assert EventName.belowEngageSpeed not in events.names
+  assert EventName.resumeRequired in events.names
+
+
+@pytest.mark.parametrize('minimum', [1.3888889, 10.72896])
+@pytest.mark.parametrize('speed', [-.04, 0., .5, 1.])
+def test_positive_cruise_minimum_remains_enforced(minimum, speed):
+  cp = truck_params()
+  cp.minEnableSpeed = minimum
+  cs = stopped(speed)
+  cs.standstill = speed <= 0.
+  events = CarEvents(cp).update(cs, cs, structs.CarControl(enabled=True))
+  assert EventName.belowEngageSpeed in events.names
+
+
+@pytest.mark.parametrize('guard,expected', [('reverse', EventName.reverseGear), ('park', EventName.wrongGear),
+                                          ('acc', EventName.accFaulted), ('brake', EventName.preEnableStandstill)])
+def test_zero_minimum_preserves_physical_guards(guard, expected):
+  cp = truck_params()
+  cs, previous = stopped(-.008), stopped(0.)
+  if guard in ('reverse', 'park'):
+    cs.gearShifter = guard
+  elif guard == 'acc':
+    cs.accFaulted = True
+  else:
+    cs.brakePressed = True
+  events = CarEvents(cp).update(cs, previous, structs.CarControl(enabled=True))
+  assert expected in events.names
+
+
+def test_combined_authority_survives_repeated_standstill_undershoot():
+  with OpenpilotPrefix(), ExitStack() as cleanup:
+    case = fixture.IoniqAvailabilityTests(methodName='runTest')
+    cleanup.callback(case.doCleanups)
+    sd, _, step = case._authority_callers(True, cp=truck_params(), genuine_events=True)
+    sd.aol_settings = read_settings(sd.params)
+    for tick, speed in enumerate((.02, 0., -.00876117, -.0001, 0., .002) * 4):
+      axis, host, control = step(tick, observed_state=stopped(speed))
+      assert host.enabled and host.active
+      assert EventName.belowEngageSpeed not in sd.events.names
+      assert axis.desiredLongitudinal and axis.longitudinalActive and axis.nativeAcknowledged
+      assert control.longActive
+    # The eligibility correction cannot bypass a native denial or driver brake.
+    _, _, control = step(24, observed_state=stopped(0.), long_allowed=False)
+    assert not control.longActive
+    cs = stopped(0.)
+    cs.brakePressed = True
+    _, _, control = step(25, observed_state=cs)
+    assert not control.longActive
diff --git a/prebuilt.json b/prebuilt.json
index 9117c39c78..39250dab58 100644
--- a/prebuilt.json
+++ b/prebuilt.json
@@ -1 +1 @@
-{"protected_inventory_sha256": "8f7fd549cacfbb5446c8d17beaab23058f0fe4aa281103879f0c0ea7518a783a", "schema_version": 1}
+{"protected_inventory_sha256": "ce5c13c592d47b0af435cf12ab99363accf3127421eaa4bcae7a2e2ae60de4a0", "schema_version": 1}