clearpilot/sessions/2026-04-26-1143-gps-disable-and-calibrationd-stale/README.md

# Session: 2026-04-26 — GPS disabled in locationd; calibrationd-still-stale notes

## Context

Followup session to `2026-04-26-0914-baseline-revert-and-parked-mode`.
After the baseline restore, the manager wouldn't start cleanly and the car
exhibited a "drifting right on straight roads, model rescues us mid-curve"
symptom. This session unblocked the startup chain end-to-end so the car can
boot and run, disabled GPS as an input to locationd (the actual fix that
made the drift go away), and pinned down — but did **not** solve — why
`liveCalibration.valid` is still stuck at `False` and what that latently
breaks downstream.

Pre-session tip: `27cad05`. Single combined commit covering four code
changes plus this README:

- `selfdrive/boardd/boardd.cc` — `safety_setter_thread` on ignition edge
- `selfdrive/controls/controlsd.py` — drop unregistered
  `no_lat_lane_change` Params write, wire `FPCC.noLatLaneChange` for UI
- `cereal/services.py` — deviceState/managerState back to 2Hz to match
  restored `DT_TRML`
- `selfdrive/locationd/locationd.cc` — ignore GPS as Kalman input
  (reversible flag)

---

## Commit 1: boardd — safety_setter_thread on ignition edge

### Symptom

Manager started fine but `controlsd_parked` blocked indefinitely at:

```
set_obd_multiplexing (selfdrive/car/fw_versions.py:236)
  fingerprint (selfdrive/car/car_helpers.py:149)
    get_car (selfdrive/car/car_helpers.py:210)
      __init__ (selfdrive/car/card.py:60)
        main (selfdrive/controls/controlsd_parked.py:41)
```

`set_obd_multiplexing` does `params.get_bool("ObdMultiplexingChanged", block=True)` —
it waits for **boardd's `safety_setter_thread`** to ack. That thread spawns
only on the **rising edge of `IsOnroad`** (`boardd.cc:476`). `IsOnroad` is set
by manager from the `started` flag (`helpers.py:49`). With the parked-mode split
from the prior session, `started` requires `not_parked`, which requires thermald
to see `carState.gearShifter != park`, which requires `controlsd_parked` to
publish carState — which it can't do until OBD multiplexing is acked.

Classic deadlock: ignition rising no longer implies IsOnroad rising.

### Fix

`selfdrive/boardd/boardd.cc:476` — change the trigger from IsOnroad rising
edge to **ignition rising edge**. Adds `bool ignition_last = false;` next to
`is_onroad_last`, swaps the gate variable, sets `ignition_last = ignition;`
after. Restores stock openpilot's intent: set safety as soon as the bus is
alive. Both controlsd variants need it; the thread's phase 2 (waiting on
`ControlsReady`) is harmless in parked mode — it just sits.

`is_onroad`/`is_onroad_last` left in place; they're now unused beyond this
gate but the read of `params.getBool("IsOnroad")` still happens, in case any
future logic wants it.

---

## Commit 2: controlsd — drop unregistered Params write

### Symptom

After the boardd fix, controlsd_parked progressed but full controlsd
crashed at first `state_control` cycle:

```
File "selfdrive/controls/controlsd.py", line 693, in state_control
    self.params_memory.put_bool("no_lat_lane_change", False)
common.params_pyx.UnknownKeyName: b'no_lat_lane_change'
```

The baseline-restored controlsd unconditionally writes `no_lat_lane_change`
to memory params on every state_control cycle. That key was never
registered in `common/params.cc`. Pre-revert (`62a403d`) controlsd didn't
write the param at all — it set `self.FPCC.noLatLaneChange` (capnp field).
The baseline brought back a code path the fork's params.cc never matched.

### Fix

In `selfdrive/controls/controlsd.py:687-694`, remove the two
`params_memory.put_bool("no_lat_lane_change", ...)` calls and replace with
`self.FPCC.noLatLaneChange = True/False` (matches what the kept UI code in
`onroad.cc:897` and `ui.cc:122` is reading from cereal). The
`frogpilot_variables.no_lat_lane_change` writes were already there — those
are what the kept Hyundai carcontroller actually reads at 100Hz.

No actuator change. Pure plumbing.

---

## Commit 3: services.py — restore deviceState/managerState rates

### Symptom

After fixing the controlsd crash, controlsd booted but immediately fired
**continuous `commIssue`** with:

```
"not_freq_ok": ["deviceState", "managerState"]
```

### Diagnosis

`common/realtime.py` was reverted to `DT_TRML = 0.5` (thermald → 2Hz) in
the baseline restore. But `cereal/services.py` still declared `deviceState`
and `managerState` at 5Hz from earlier 4Hz-fan-control work. The freq window
is `[0.8 × min, 1.2 × max]` — declared 5Hz means [4.0, 6.0]Hz. Thermald
publishing at 2Hz fell well below 4.0 → freq_ok=False every cycle →
commIssue every cycle.

Already documented as a known footgun in `CLAUDE.md` ("Changing a Service's
Publish Rate").

### Fix

`cereal/services.py:33,73` — set both back to 2Hz with a comment pointing
at `DT_TRML`. After this, `not_freq_ok=[]` and the continuous commIssue
stopped — only one transient commIssue at startup remained (warmup).

---

## Commit 4: locationd — ignore GPS as Kalman input (reversible)

### Why

The car was drifting right on straight roads. Pre-revert, the user
reported this had been working for years; the only practically-new thing
is that `system/clearpilot/gpsd.py` (AT-command-based GPS) had recently
**started actually getting fixes**, where for a long time it wasn't.

Two concrete data problems with the GPS feed for selfdrive purposes:

- `gpsd.py:221` hard-codes `gps.vNED = [0.0, 0.0, 0.0]` while the user is
  moving 28 m/s. locationd's `handle_gps` derives `OBSERVATION_ECEF_VEL`
  from this; the Kalman gets "GPS says you're stopped" while accelerometer
  says otherwise.
- `gpsd.py:216,222` populate horizontalAccuracy/verticalAccuracy from
  `hdop * 5` (a rough conversion); `bearingAccuracyDeg = 10.0` and
  `speedAccuracy = 1.0` are constants. None of these match what a real
  GNSS chip reports.

These flow into the latcontrol_torque pipeline indirectly through
`liveLocationKalman.angularVelocityCalibrated` (used as
`actual_curvature_llk = ... / CS.vEgo` blended with steering-angle-derived
curvature) and through `liveLocationKalman.calibratedOrientationNED`
(pitch). When the Kalman has wrong velocity observations, those derived
fields go wrong — and on a straight crowned road, the controller's
"actual_curvature" picture is off-center, biasing torque output.

### What the user does NOT want disabled

gpsd publishes are still consumed by:
- UI speed indicator and the ClearPilot status overlay
- `dashcamd` for `.srt` subtitle sidecars (lat/lon per segment)
- `timed.py` for system-clock setting via `unixTimestampMillis`
- `gpsd.py` itself for sunset/sunrise → `IsDaylight` (auto night mode)
- `telemetryd.py` for the `gps` group in the CSV

So we cannot just stop publishing — only locationd should ignore.

### Fix

`selfdrive/locationd/locationd.cc:310-323` — add a `clearpilot_disable_gps`
const at the top of `Localizer::handle_gps` and OR it into the existing
reject condition. With it true, every gpsLocation message falls through to
`determine_gps_mode(current_time)` (openpilot's stock no-GPS path:
`input_fake_gps_observations` once position uncertainty grows past
`SANE_GPS_UNCERTAINTY`, otherwise nothing). `last_gps_msg` never updates,
`is_gps_ok()` returns False, `liveLocationKalman.gpsOK = false`.

Effect verified by user: drift improved noticeably. The torque controller
is no longer fed contradictory GPS-vs-IMU velocity observations through
the Kalman.

To re-enable GPS as a Kalman input: flip the `clearpilot_disable_gps`
constant to `false` and rebuild. Self-contained edit.

---

## Calibrationd: still stale, root-cause partially understood

### What is happening

`calibrationd` publishes `liveCalibration.valid = sm.all_checks()` on every
cycle, where `sm` polls `cameraOdometry` and non-polls `carState` and
`carParams`. We measured: **120 publishes in 30 seconds, every single one
`valid=False`** with `calStatus=calibrated, calPerc=100, validBlocks=50`.
The body of the calibration is converged — the validity flag is stuck off.

### Why this matters

`liveCalibration.valid=False` cascades:

1. `locationd.cc:715` — `filterInitialized = sm.allAliveAndValid()`.
   liveCalibration is in the sub list and not in `ignore_alive` /
   `ignore_valid`. So filterInitialized stays False forever.
2. With Kalman uninitialized, `liveLocationKalman` still publishes but the
   body fields are empty/default. `liveLocationKalman.status = uninitialized`.
3. `paramsd.py` subscribes to `liveLocationKalman` with `poll='liveLocationKalman'`
   and gates its update logic on `sm.all_checks()`. When liveLocationKalman
   itself isn't in a sane state, paramsd's `roll`, `angleOffsetDeg`,
   `steerRatio`, `stiffnessFactor` either never converge or converge to bad
   values.
4. `latcontrol_torque.py:135-136` uses `params.angleOffsetDeg` to compute
   `actual_curvature_vm` and `params.roll` for `roll_compensation`. With
   `roll=0`, no compensation for a crowned/banked road. With wrong
   `angleOffsetDeg`, the closed-loop "actual curvature" measurement is
   biased.

So the latent risk is: even with our GPS fix, the controller is running
**without learned roll compensation and without a learned steering-angle
offset**. Symptom-free on straight, level pavement; biased on banked roads.

### Why `valid=False`

Inside calibrationd's SubMaster, `sm.all_checks() = all_alive AND all_freq_ok
AND all_valid`. We measured each:

- `cameraOdometry`: alive=True, valid=True, freq_ok=True ✓
- `carState`: alive flickers True/False, valid=True, **freq_ok=False (every cycle)**
- `carParams`: alive=True after first arrival, valid=True, freq_ok=False
  but excluded from `all_freq_ok` because `_check_avg_freq` skips services
  with `frequency < 0.99` Hz (carParams is 0.02 Hz declared) — so it doesn't
  fail the gate.

The smoking gun is **`carState.freq_ok = False` from inside calibrationd's
`poll='cameraOdometry'` SubMaster**.

Direct measurement (`/tmp/test_subs.py`):

| poll arg | carState observed rate | freq_ok |
|---|---:|:-:|
| `None` (all polled) | 97.40 Hz | True |
| `'cameraOdometry'` | **2.24 Hz** | **False** |
| `'carState'` | 98.58 Hz | True |

carState is published at 100 Hz to a 10MB shared-memory MSGQ queue. From
inside `poll='cameraOdometry'`, our non-blocking `recv_one_or_none(carState)`
returns None ~88% of the time. `/tmp/diag_recv.py`:

```
cameraOdometry msgs received: 121
carState recv calls: 121, hits: 14 (11.6% hit rate)
avg cycle duration: 50.0ms
```

So we're calling `recv` 20× per second on carState's queue, and finding
the queue empty 9 out of 10 times — even though carState is being published
at 100 Hz to that same queue with a `conflate=True` socket option.

### The MSGQ NUM_READERS = 12 hypothesis

`cereal/messaging/msgq.h:9` defines `#define NUM_READERS 12`. When a 13th
subscriber tries to subscribe to a queue, `msgq.cc:182-197` **invalidates
ALL readers simultaneously** (`*q->read_valids[i] = false` for all i)
to "reset and re-register". On the next read, an invalidated reader's
`msgq_msg_recv` jumps to `msgq_reset_reader` (line 347) and ends up with
`read_pointer == write_pointer` (caught up to current), returning size 0.

Subscribers to `carState` in our running system include: controlsd,
plannerd, locationd, calibrationd, paramsd, dmonitoringd, frogpilot_process,
telemetryd, statsd. That's already nine. The introspection scripts
(`/tmp/check_*.py`, `/tmp/measure_freq.py`, `/tmp/diag_recv.py`,
`/tmp/cal_view.py`) and any UI-side subscribers add more, can easily
push past 12 and trigger global eviction. Once evicted, a long-running
subscriber stays in the "find empty queue / reset / try again" loop, which
is what we measured.

This is **partially confirmed** but not proven definitively. The
investigation was paused before instrumenting the queue header to count
slot churn. The smoking-gun would be: print `q->num_readers` from inside
calibrationd at boot vs. during steady state and watch it tick up to 12+.

### Things to consider for the actual fix

1. **`7ee923b` already solved this exact problem.** It changed
   calibrationd's publish to:
   ```python
   # was: calibrator.send_data(pm, sm.all_checks())
   # to:  calibrator.send_data(pm, calibrator.cal_status == log.LiveCalibrationData.Status.calibrated)
   ```
   The commit message documented the exact failure mode (cascade through
   locationd uninitialized → paramsd steerRatio≈0 / stiffnessFactor≈0 →
   nonsense curvature commands). It was reverted by `47321e3` as part of
   "restore driving logic to pre-variable-fps baseline" — but that revert
   was about isolating the drift cause, and the calibrationd change here
   is *not* in the variable-FPS family. **Re-applying `7ee923b` is
   probably the right next move**, narrowly scoped to calibrationd.py.
2. Less attractive alternatives: bump `NUM_READERS`; switch
   carState to `poll=None` in calibrationd (more cycles per update,
   higher CPU); add `ignore_average_freq=['carState']` to calibrationd's
   SubMaster (treats freq glitches as benign, but keeps the cascade for
   alive/valid).

---

## Steer-fault alert investigation (separate symptom)

User saw "Steering Temporarily Unavailable" alerts during a test drive
even though we hadn't touched lateral-control code. Captured in
`realdata/00000081--528e2aa03a--0/rlog`:

- Faults occur in **brief 50–100 ms pulses** clustered while moving slowly
  (`vEgo` 2.7–5.2 m/s ≈ 6–12 mph).
- Each pulse correlates with **large driver wheel torque** (-250, +273,
  -187, +119 Nm) — i.e. the user actively turning the wheel during a
  parking-lot maneuver.
- `cruise.enabled = False` throughout — openpilot was not engaged.
- The car's MDPS sets `LKA_FAULT` at low speeds when torque is high; that
  bit maps directly to `cs_out.steerFaultTemporary` (`carstate.py:259`),
  which fires `steerTempUnavailableSilent` regardless of engagement
  (`ET.WARNING` displays unconditionally).

User reports they've "never had this issue before" — implying earlier
ClearPilot revisions either gated the fault on speed or used a different
no-lateral path. **Not confirmed which.** Open follow-up.

---

## Open follow-ups (ordered by likely return)

1. **Re-apply `7ee923b`** — gate `liveCalibration.valid` on `calStatus`,
   not `sm.all_checks()`. Unblocks locationd init → paramsd convergence →
   real `params.roll` and `params.angleOffsetDeg` for the torque
   controller. Latent benefit beyond what GPS-disable alone gave us.
2. **Investigate the persistent low-speed `steerTempUnavailable` alert.**
   Either (a) gate `steerFaultTemporary` on `vEgo > ~8 m/s` in
   `carstate.py:259`, or (b) find what the previous fork did — possibly
   stopped sending tester CAN messages on park, possibly suppressed the
   alert specifically during a park transition window.
3. **Suppress LKAS fault display when shifting drive → park.** The user
   reports the car shows an LKAS-fault icon when openpilot keeps publishing
   tester-present CAN messages after entering park. Investigation needed
   in `selfdrive/car/hyundai/carcontroller.py` and `hyundaicanfd.py` to
   gate tester messages on gear ≠ park.
4. **Wheel-torque headroom edit.** User mentioned a community-known edit
   that allows slightly higher steering torque on the Hyundai panda safety
   model. Research target: panda safety code for HYUNDAI_CANFD safety
   model and the `MAX_TORQUE` / per-cycle delta limits.
5. **Single startup `commIssue` event.** Even with all our fixes, controlsd
   logs one transient commIssue right after `controlsd.initialized`
   (timeout=true after 6s). The `invalid` set at that moment is
   downstream services still warming up (liveCalibration, liveLocationKalman,
   liveParameters, liveTorqueParameters, frogpilotPlan, longitudinalPlan,
   driverMonitoringState). Most should clear once the calibrationd issue
   is fixed; remaining ones are normal warmup.
6. **gpsd.py vNED / accuracy fields.** Out of scope for this session
   (we disabled GPS in locationd instead), but if GPS is ever re-enabled,
   `gpsd.py:216,221-224` need real values: vNED from
   `speed × {cos(bearing), sin(bearing), 0}`, and accuracy fields from
   actual modem reports rather than hard-coded constants.