Add

device_server.py

@@ -42,6 +42,39 @@ REGISTER_COMMANDS = [
 SN65_I2C_BUS  = 4      # i2c-4 on this board
 SN65_I2C_ADDR = 0x2C   # SN65DSI83 fixed 7-bit I2C address
 
+# Settling-period poll — started in a background thread immediately after each
+# kiosk kill+restart.  Samples csr_0a and csr_e5 every SETTLING_INTERVAL_S for
+# SETTLING_DURATION_S seconds.  Results stored in _settling_log and returned by
+# GET /sn65_settling so the host can correlate DSI errors with LP captures.
+SETTLING_DURATION_S  = 1.5    # seconds to poll after restart
+SETTLING_INTERVAL_S  = 0.010  # 10 ms between I2C reads
+
+_settling_log:  list = []
+_settling_lock: threading.Lock = threading.Lock()
+
+
+def _run_settling_poll() -> None:
+    """Poll SN65DSI83 csr_0a + csr_e5 at 10 ms intervals for 1.5 s after restart."""
+    t_start = time.time()
+    t_end   = t_start + SETTLING_DURATION_S
+    readings: list = []
+    while time.time() < t_end:
+        t_ms = round((time.time() - t_start) * 1000, 1)
+        val_0a, _ = _i2c_read_byte(SN65_I2C_BUS, SN65_I2C_ADDR, 0x0A)
+        val_e5, _ = _i2c_read_byte(SN65_I2C_BUS, SN65_I2C_ADDR, 0xE5)
+        readings.append({
+            "t_ms":      t_ms,
+            "csr_0a":    f"0x{val_0a:02x}" if val_0a is not None else None,
+            "csr_e5":    f"0x{val_e5:02x}" if val_e5 is not None else None,
+            "pll_lock":  bool(val_0a & 0x80) if val_0a is not None else None,
+            "clk_det":   bool(val_0a & 0x08) if val_0a is not None else None,
+            "any_error": bool(val_e5)         if val_e5 is not None else None,
+        })
+        time.sleep(SETTLING_INTERVAL_S)
+    with _settling_lock:
+        _settling_log.clear()
+        _settling_log.extend(readings)
+
 # Known Samsung DSIM register names (base 0x32E10000, i.MX 8M Mini)
 _DSIM_NAMES = {
     0x32e10004: "DSIM_STATUS",
@@ -107,6 +140,9 @@ def control_display():
                         _video_proc.kill()
                         _video_proc.wait()
                 time.sleep(0.15)   # let DSI reach LP-11
+                # Start settling poll immediately — captures csr_e5 error flags
+                # during DSI startup so the host can determine root cause of flicker.
+                threading.Thread(target=_run_settling_poll, daemon=True).start()
                 try:
                     log = open("/tmp/kiosk.log", "w")
                     _video_proc = subprocess.Popen(
@@ -182,6 +218,21 @@ def _i2c_read_byte(bus: int, addr: int, reg: int) -> tuple[int | None, str]:
         return None, str(e)
 
 
+@app.route("/sn65_settling", methods=["GET"])
+def get_sn65_settling():
+    """Return the most recent post-restart settling poll (csr_0a + csr_e5 over 1.5 s)."""
+    with _settling_lock:
+        readings = list(_settling_log)
+    error_readings = [r for r in readings if r.get("any_error")]
+    return jsonify({
+        "n_readings":     len(readings),
+        "n_error":        len(error_readings),
+        "duration_s":     SETTLING_DURATION_S,
+        "interval_ms":    int(SETTLING_INTERVAL_S * 1000),
+        "readings":       readings,
+    }), 200
+
+
 @app.route("/sn65_registers", methods=["GET"])
 def get_sn65_registers():
     """Read SN65DSI83 CSR 0x0A (PLL/CLK status) and 0xE5 (error flags) via I2C."""