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Add Tools/Diagnostics: thread-safe DTC read/clear + Diagnostics panel

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The polling thread owns the ELM327, so reading/clearing trouble codes from
the GUI thread would race PID reads and corrupt the stream. Add a one-off
command path that serializes ad-hoc link work onto the polling thread.

obdcore/scheduler.py:
- PollScheduler.run_oneoff(fn, timeout) enqueues a callable (queue.Queue +
  threading.Event) and blocks for its result, re-raising the callable's
  exception. tick() drains queued one-offs at its very top, so they run on
  the same thread that does PID reads -- never concurrently. When the
  scheduler thread isn't running, the job is drained inline on the caller
  (still serialized vs tick(), safe because nothing else touches the link).

gui/controller.py:
- Controller.read_dtcs() -> {"stored","pending","permanent"} (modes 03/07/0A,
  svc 0x43/0x47/0x4A) and clear_dtcs() -> bool. Both route through the
  scheduler one-off when a scheduler exists, else call the link directly.

gui/main.py:
- Diagnostics menu (Read Codes / Clear Codes...) and a right-side QDockWidget
  listing codes grouped Stored/Pending/Permanent. Each row is code +
  description + system from DtcDatabase; no_start codes are flagged bold red.
- Clear is guarded by a confirmation warning (erases codes + freeze frame;
  honest "the code comes right back" / permanent-codes-won't-clear tone from
  run_clear in obd_reader.py). On confirm: clear, then re-read immediately and
  show whatever returned, reporting active faults that came straight back.

tests/test_diagnostics.py:
- one-off returns its value, re-raises exceptions, is drained before a tick's
  PID reads, and runs on a live background thread while polling continues.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016yT89n4zR4qbrySoSiEyZs
This commit is contained in:
Justin Paul
2026-06-30 14:53:57 -04:00
parent f3f0bf2a77
commit 0fea0908c8
4 changed files with 374 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
gui/controller.py
+33
View File
@@ -15,6 +15,14 @@ FAST = {"ICP", "FICM_M", "RPM"}
DEFAULT_HZ = 2
FAST_HZ = 5
# DTC services: result-bucket label, request mode string, response service byte
# (mode "03"->0x43 stored, "07"->0x47 pending, "0A"->0x4A permanent)
DTC_SERVICES = (
("stored", "03", 0x43),
("pending", "07", 0x47),
("permanent", "0A", 0x4A),
)
class Controller:
def __init__(self):
@@ -79,6 +87,31 @@ class Controller:
def now(self):
return (time.time() - self.t0) if self.t0 else 0.0
# -- diagnostics (DTCs) --------------------------------------------------
# All link access goes through the scheduler's one-off path when a
# scheduler exists, so a DTC read/clear never races the polling thread for
# the serial link. When disconnected (no scheduler), call the link direct.
def _oneoff(self, fn, timeout=8.0):
if self.sched is not None:
return self.sched.run_oneoff(fn, timeout=timeout)
if self.link is not None:
return fn()
raise RuntimeError("not connected")
def read_dtcs(self):
"""Read stored (03), pending (07) and permanent (0A) DTCs.
Returns {"stored": [...], "pending": [...], "permanent": [...]}."""
out = {}
for label, mode, svc in DTC_SERVICES:
out[label] = self._oneoff(
lambda m=mode, s=svc: self.link.read_dtcs(m, s)) or []
return out
def clear_dtcs(self):
"""Mode 04: clear stored+pending codes and freeze frame.
Returns True if the ECU acknowledged."""
return bool(self._oneoff(lambda: self.link.clear_dtcs()))
def stop(self):
if self.sched:
self.sched.stop()
gui/main.py
+146
View File
@@ -45,6 +45,7 @@ class MainWindow(QtWidgets.QMainWindow):
self._build_menubar()
self._build_connection_bar()
self._build_pid_browser()
self._build_diag_dock()
self._build_center()
self._build_statusbar()
self._refresh_title()
@@ -73,6 +74,12 @@ class MainWindow(QtWidgets.QMainWindow):
self.profm = mb.addMenu("&Profile")
self._rebuild_profile_menu()
diagm = mb.addMenu("&Diagnostics")
self.read_dtc_act = self._act(diagm, "Read Codes", self._read_codes,
"Read stored / pending / permanent trouble codes")
self.clear_dtc_act = self._act(diagm, "Clear Codes…", self._clear_codes,
"Erase stored codes + freeze frame (mode 04)")
viewm = mb.addMenu("&View")
self.view_graph = self._act(viewm, "Graph View", lambda: self._set_view(0),
checkable=True)
@@ -85,6 +92,9 @@ class MainWindow(QtWidgets.QMainWindow):
self.show_pids = self._act(viewm, "Show PID Panel", self._toggle_pid_dock,
checkable=True)
self.show_pids.setChecked(True)
self.show_diag = self._act(viewm, "Show Diagnostics Panel", self._toggle_diag_dock,
checkable=True)
self.show_diag.setChecked(True)
self.norm_act = self._act(viewm, "Normalize Graph (% of range)",
self._sync_norm_from_menu, checkable=True)
viewm.addSeparator()
@@ -202,6 +212,142 @@ class MainWindow(QtWidgets.QMainWindow):
self.tree.resizeColumnToContents(0)
self.tree.blockSignals(False)
# ---------- diagnostics dock (DTCs) ----------
def _build_diag_dock(self):
self.diag_dock = QtWidgets.QDockWidget("Diagnostics", self)
wrap = QtWidgets.QWidget()
lay = QtWidgets.QVBoxLayout(wrap)
lay.setContentsMargins(4, 4, 4, 4)
bar = QtWidgets.QHBoxLayout()
self.diag_read_btn = QtWidgets.QPushButton("Read Codes")
self.diag_read_btn.clicked.connect(self._read_codes)
self.diag_clear_btn = QtWidgets.QPushButton("Clear Codes…")
self.diag_clear_btn.clicked.connect(self._clear_codes)
bar.addWidget(self.diag_read_btn)
bar.addWidget(self.diag_clear_btn)
bar.addStretch(1)
lay.addLayout(bar)
self.diag_tree = QtWidgets.QTreeWidget()
self.diag_tree.setColumnCount(3)
self.diag_tree.setHeaderLabels(["Code", "Description", "System"])
self.diag_tree.setRootIsDecorated(True)
self.diag_tree.header().setStretchLastSection(False)
self.diag_tree.header().setSectionResizeMode(
1, QtWidgets.QHeaderView.Stretch)
lay.addWidget(self.diag_tree)
self.diag_hint = QtWidgets.QLabel(
"Connect, then Read Codes. Bold red = no-start / drive-disabling.")
self.diag_hint.setWordWrap(True)
lay.addWidget(self.diag_hint)
self.diag_dock.setWidget(wrap)
self.diag_dock.visibilityChanged.connect(
lambda vis: self.show_diag.setChecked(vis))
self.addDockWidget(QtCore.Qt.RightDockWidgetArea, self.diag_dock)
_DIAG_GROUPS = [("stored", "Stored (mode 03)"),
("pending", "Pending (mode 07)"),
("permanent", "Permanent (mode 0A)")]
def _populate_diag(self, codes):
"""codes: {'stored':[...], 'pending':[...], 'permanent':[...]}"""
self.diag_tree.clear()
total = 0
for bucket, label in self._DIAG_GROUPS:
lst = codes.get(bucket, [])
total += len(lst)
top = QtWidgets.QTreeWidgetItem([f"{label} ({len(lst)})", "", ""])
f = top.font(0); f.setBold(True); top.setFont(0, f)
top.setFirstColumnSpanned(False)
self.diag_tree.addTopLevelItem(top)
if not lst:
none = QtWidgets.QTreeWidgetItem(["—", "(no codes)", ""])
none.setForeground(1, QtGui.QBrush(QtGui.QColor("#888")))
top.addChild(none)
for code in lst:
d = self.ctl.dtcdb.get(code)
it = QtWidgets.QTreeWidgetItem([code, d.desc, d.system])
it.setData(0, QtCore.Qt.UserRole, code)
if getattr(d, "no_start", False):
red = QtGui.QBrush(QtGui.QColor("#e6194B"))
bf = it.font(0); bf.setBold(True)
for c in range(3):
it.setFont(c, bf)
it.setForeground(c, red)
it.setToolTip(0, "No-start / drive-disabling fault")
top.addChild(it)
top.setExpanded(True)
self.diag_tree.resizeColumnToContents(0)
self.diag_tree.resizeColumnToContents(2)
return total
def _read_codes(self):
if not self.ctl.connected:
QtWidgets.QMessageBox.information(
self, "Not connected", "Connect (or tick Mock) before reading codes.")
return
try:
codes = self.ctl.read_dtcs()
except Exception as e:
QtWidgets.QMessageBox.critical(self, "Read failed", str(e))
return
total = self._populate_diag(codes)
self.diag_dock.setVisible(True)
self.show_diag.setChecked(True)
self.status.showMessage(
f"Read codes: {total} found "
f"(stored {len(codes.get('stored', []))}, "
f"pending {len(codes.get('pending', []))}, "
f"permanent {len(codes.get('permanent', []))})."
if total else "Read codes: none stored.")
def _clear_codes(self):
if not self.ctl.connected:
QtWidgets.QMessageBox.information(
self, "Not connected", "Connect (or tick Mock) before clearing codes.")
return
btn = QtWidgets.QMessageBox.warning(
self, "Clear codes?",
"This erases stored + pending codes AND freeze-frame data, and "
"resets emissions monitors.\n\n"
"Write the codes down first — and read them on a no-start before "
"clearing. If the fault is still present the code comes right back.\n"
"Permanent codes (mode 0A) will NOT clear until the fault is fixed "
"and the vehicle self-clears them over several drive cycles.\n\n"
"Clear codes now?",
QtWidgets.QMessageBox.Yes | QtWidgets.QMessageBox.No,
QtWidgets.QMessageBox.No)
if btn != QtWidgets.QMessageBox.Yes:
self.status.showMessage("Cancelled. No codes cleared.")
return
try:
ok = self.ctl.clear_dtcs()
except Exception as e:
QtWidgets.QMessageBox.critical(self, "Clear failed", str(e))
return
if not ok:
QtWidgets.QMessageBox.warning(
self, "No acknowledgement",
"The ECU did not acknowledge the clear.\n"
"Make sure the key is in RUN and the vehicle is connected, then "
"try again.")
self.status.showMessage("Clear not acknowledged by ECU.")
return
# Re-read immediately so anything that came straight back is shown.
try:
codes = self.ctl.read_dtcs()
except Exception:
codes = {}
returned = self._populate_diag(codes)
if returned:
self.status.showMessage(
f"Cleared — but {returned} code(s) returned immediately "
"(active fault present).")
else:
self.status.showMessage("Cleared. No codes on re-read.")
def _toggle_diag_dock(self):
self.diag_dock.setVisible(self.show_diag.isChecked())
# ---------- center (graph + table stack) ----------
def _build_center(self):
self.stack = QtWidgets.QStackedWidget()