fix(firmware): stop ESP32-S3 sendto ENOMEM tight loop - 10 Hz self-ping, 300 ms backoff, 128 TX buffers (#1135)

firmware/esp32-csi-node/main/adaptive_controller.c

@@ -225,7 +225,7 @@ static void fast_loop_cb(TimerHandle_t t)
      * the default 200 ms fast period), which combined with CSI promiscuous
      * RX saturated the WiFi TX airtime — measured live on COM8 (S3) and
      * COM9 (C6): every adaptive cycle showed `sendto ENOMEM — backing off
-     * for 100 ms`, and bumping LWIP/WiFi buffer pools to 4× had no effect
+     * for the ENOMEM cooldown`, and bumping LWIP/WiFi buffer pools to 4× had no effect
      * on the rate because the bottleneck was radio TX time, not pool size.
      * Dropping to 1 Hz (5× less feature_state traffic) frees the TX queue
      * for CSI sends and lands well within the spec. */

firmware/esp32-csi-node/main/csi_collector.c

@@ -376,7 +376,7 @@ static void wifi_promiscuous_cb(void *buf, wifi_promiscuous_pkt_type_t type)
  * are sparse beacons (often non-OFDM DSSS), so wifi_csi_callback can starve to
  * yield=0pps -> DEGRADED -> motion/presence=0 (#521, #954).
  *
- * This guarantees a ~50 Hz OFDM unicast floor by pinging the STA's own gateway:
+ * This guarantees a ~10 Hz OFDM unicast floor by pinging the STA's own gateway:
  * the router's ICMP echo replies are OFDM frames destined to this station, which
  * drive the CSI engine regardless of promiscuous filter state or ambient traffic.
  * It is ADDITIVE — promiscuous capture (#396/#893) is left fully intact so
@@ -409,7 +409,9 @@ static void csi_start_self_ping(void)
     esp_ping_config_t cfg = ESP_PING_DEFAULT_CONFIG();
     cfg.target_addr     = target;
     cfg.count           = ESP_PING_COUNT_INFINITE;
-    cfg.interval_ms     = 20;     /* 50 Hz -> ~50 received OFDM replies/sec */
+    cfg.interval_ms     = 100;    /* 10 Hz: cut self-ping TX flood that exhausts
+                                     S3 WiFi TX buffers -> sendto ENOMEM (#1135).
+                                     10 Hz still keeps the CSI OFDM source alive. */
     cfg.data_size       = 1;
     cfg.task_stack_size = 4096;
 
@@ -422,7 +424,7 @@ static void csi_start_self_ping(void)
 
     if (esp_ping_new_session(&cfg, &cbs, &s_self_ping) == ESP_OK && s_self_ping != NULL) {
         esp_ping_start(s_self_ping);
-        ESP_LOGI(TAG, "self-ping started -> %s @50Hz (CSI OFDM source, fix #521/#954)", gw_str);
+        ESP_LOGI(TAG, "self-ping started -> %s @10Hz (CSI OFDM source, fix #521/#954, S3 ENOMEM #1135)", gw_str);
     } else {
         ESP_LOGW(TAG, "self-ping: esp_ping_new_session failed");
         s_self_ping = NULL;

firmware/esp32-csi-node/main/stream_sender.c

@@ -26,7 +26,8 @@ static struct sockaddr_in s_dest_addr;
  * rapid-fire CSI callbacks can exhaust the pbuf pool and crash the device.
  */
 static int64_t s_backoff_until_us = 0;       /* esp_timer timestamp to resume */
-#define ENOMEM_COOLDOWN_MS  100              /* suppress sends for 100 ms */
+#define ENOMEM_COOLDOWN_MS  300              /* suppress sends for 300 ms — 100 ms
+                                              * was too short to drain on S3 (#1135) */
 #define ENOMEM_LOG_INTERVAL 50               /* log every Nth suppressed send */
 static uint32_t s_enomem_suppressed = 0;
 

firmware/esp32-csi-node/sdkconfig.defaults

@@ -41,7 +41,7 @@ CONFIG_LWIP_SO_RCVBUF=y
 # ~3 KB extra heap cost, measured live on both targets Jun 8 2026.
 CONFIG_LWIP_UDP_RECVMBOX_SIZE=32
 CONFIG_LWIP_TCPIP_RECVMBOX_SIZE=64
-CONFIG_ESP_WIFI_DYNAMIC_TX_BUFFER_NUM=64
+CONFIG_ESP_WIFI_DYNAMIC_TX_BUFFER_NUM=128
 # NOTE: Empirical 25 s measurements on the S3 at COM8 showed these bumps
 # eliminate the csi_collector.sendto failure path (`fail #1..5` →
 # `fail #0`) — real improvement — but do NOT eliminate the broader

firmware/esp32-csi-node/sdkconfig.defaults.esp32c6

@@ -70,6 +70,13 @@ CONFIG_LWIP_SO_RCVBUF=y
 CONFIG_ESP_MAIN_TASK_STACK_SIZE=8192
 CONFIG_FREERTOS_TIMER_TASK_STACK_DEPTH=8192
 
+# ── Wi-Fi dynamic TX buffers: pin to the C6's verified value ──
+# The S3 ENOMEM fix (#1135) raises CONFIG_ESP_WIFI_DYNAMIC_TX_BUFFER_NUM to 128
+# in the base sdkconfig.defaults. That fix was hardware-verified on the S3 only,
+# so keep the C6 build at its previously-shipping 64 rather than silently
+# inheriting 128 on an untested target. Re-tune here if the C6 ever needs it.
+CONFIG_ESP_WIFI_DYNAMIC_TX_BUFFER_NUM=64
+
 # ── Power: keep CPU at max 160 MHz (C6 ceiling) for DSP throughput ──
 CONFIG_ESP_DEFAULT_CPU_FREQ_MHZ_160=y
 CONFIG_ESP_DEFAULT_CPU_FREQ_MHZ=160