chestnut: skip big model compile when source is LFS pointer (#38655)

Applied upstream commit b8e14d85: helpers add big_model_source_available,
SConscript skips big model build if big_driving_supercombo.onnx is missing
or an LFS pointer, hardwared uses the compiled helper.

openpilot/selfdrive/modeld/SConscript

@@ -7,7 +7,7 @@ from openpilot.common.file_chunker import chunk_file, get_chunk_targets, get_exi
 from openpilot.common.transformations.camera import _ar_ox_fisheye, _os_fisheye
 from openpilot.common.transformations.model import MEDMODEL_INPUT_SIZE, DM_INPUT_SIZE
 from openpilot.selfdrive.modeld.constants import ModelConstants
-from openpilot.selfdrive.modeld.helpers import TG_INPUT_DEVICES_PATH, usbgpu_present, modeld_pkl_path
+from openpilot.selfdrive.modeld.helpers import TG_INPUT_DEVICES_PATH, big_model_source_available, usbgpu_present, modeld_pkl_path
 
 
 CAMERA_CONFIGS = [
@@ -44,6 +44,10 @@ tg_devices = { # which device to put jit inputs to at runtime
 }
 
 USBGPU = usbgpu_present()
+if USBGPU and not big_model_source_available():
+  print("Big model source unavailable, skipping big model build")
+  USBGPU = False
+
 if USBGPU:
   usbgpu_tg_flags = f'DEBUG=2 DEV=USB+AMD:LLVM WARP_DEV={tg_backend} FLOAT16=1 JIT_BATCH_SIZE=0 GMMU=0 TC_OPT=2'
   # the USB+AMD GPU takes an exclusive flock; serialize all targets that touch it

openpilot/selfdrive/modeld/helpers.py

@@ -21,6 +21,10 @@ def modeld_pkl_path(usbgpu: bool):
   prefix = 'big_' if usbgpu else ''
   return MODELS_DIR / f'{prefix}driving_tinygrad.pkl'
 
+def big_model_source_available() -> bool:
+  model_path = MODELS_DIR / 'big_driving_supercombo.onnx'
+  return model_path.is_file() and model_path.stat().st_size >= 1024
+
 def dump_oob(obj, f):
   with tempfile.TemporaryFile(dir=".") as tmp:
     def buffer_callback(pb: pickle.PickleBuffer):

openpilot/system/hardware/hardwared.py

@@ -16,6 +16,7 @@ from openpilot.common.utils import strip_deprecated_keys
 from openpilot.common.filter_simple import FirstOrderFilter
 from openpilot.common.params import Params
 from openpilot.common.realtime import DT_HW
+from openpilot.selfdrive.modeld.helpers import usbgpu_compiled
 from openpilot.selfdrive.selfdrived.alertmanager import set_offroad_alert
 from openpilot.common.hardware import HARDWARE, COMMA_HARDWARE
 from openpilot.common.basedir import BASEDIR
@@ -238,8 +239,7 @@ def hardware_thread(end_event, hw_queue) -> None:
 
   fan_controller = FanController(int(1./DT_HW))
   chestnut = Chestnut()
-  big_model_available = os.path.isfile(os.path.join(BASEDIR, "openpilot/selfdrive/modeld/models/big_driving_supercombo.onnx")) or \
-                        os.path.isfile(os.path.join(BASEDIR, "openpilot/selfdrive/modeld/models/big_driving_tinygrad.pkl.chunkmanifest"))
+  big_model_available = usbgpu_compiled()
 
   while not end_event.is_set():
     sm.update(PANDA_STATES_TIMEOUT)