From 4d779cd972dadc0d30ef223929fb75d936bd9059 Mon Sep 17 00:00:00 2001
From: proddy <paul@derbyshire.nl>
Date: Sat, 17 Oct 2026 13:49:11 +0200
Subject: [PATCH] more tests for #3094

---
 src/core/emsesp.cpp | 35 ++++++++++++++++++++++++++++++++++-
 src/core/emsesp.h   |  3 +++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/src/core/emsesp.cpp b/src/core/emsesp.cpp
index 5e5b7db0b..75ef88c52 100644
--- a/src/core/emsesp.cpp
+++ b/src/core/emsesp.cpp
@@ -57,6 +57,7 @@ uint32_t EMSESP::gateway_window_start_      = 0;
 uint8_t  EMSESP::gateway_window_count_      = 0;
 uint32_t EMSESP::gateway_fast_start_        = 0;
 uint8_t  EMSESP::gateway_fast_count_        = 0;
+uint32_t EMSESP::gateway_last_seen_         = 0;
 uint8_t  EMSESP::last_version_request_src_  = 0;
 uint32_t EMSESP::last_version_request_time_ = 0;
 #endif
@@ -1598,6 +1599,8 @@ bool EMSESP::add_device(const uint8_t device_id, const uint8_t product_id, const
 #ifdef EMSESP_GATEWAY_TX_HOLD
     // a gateway appearing while we're running is most likely starting up and about to sync
     if (device_id == EMSdevice::EMS_DEVICE_ID_GATEWAY1) {
+        uint32_t now       = uuid::get_uptime();
+        gateway_last_seen_ = now ? now : 1;
         gateway_tx_hold_start();
     }
 #endif
@@ -1781,6 +1784,13 @@ void EMSESP::incoming_telegram(uint8_t * data, const uint8_t length) {
             wait_km_ = false; // KM200 is polled, from now on it is safe to send
         }
 
+#ifdef EMSESP_GATEWAY_TX_HOLD
+        // master polling 0x48 again after a gap means the gateway (or heat pump) came back
+        if (poll_id == EMSdevice::EMS_DEVICE_ID_GATEWAY1) {
+            gateway_note_activity();
+        }
+#endif
+
 #ifdef EMSESP_UART_DEBUG
         char s[4];
         if (first_value & 0x80) {
@@ -1853,9 +1863,32 @@ void EMSESP::scheduled_fetch_values() {
 }
 
 #ifdef EMSESP_GATEWAY_TX_HOLD
+// any poll of or telegram from 0x48 — if it was silent (HP/K30RF restart) re-arm the Tx hold
+void EMSESP::gateway_note_activity() {
+    uint32_t now = uuid::get_uptime();
+    if (gateway_last_seen_ && (now - gateway_last_seen_ > GATEWAY_SILENCE_MS)) {
+        // a real reconnect: allow hold even if we were in the post-max cooldown
+        gateway_cooldown_until_ = 0;
+        LOG_INFO("Gateway 0x%02X returned after %lu s silence, holding Tx",
+                 EMSdevice::EMS_DEVICE_ID_GATEWAY1,
+                 (unsigned long)((now - gateway_last_seen_) / 1000));
+        if (!gateway_hold_until_) {
+            gateway_hold_start_ = now;
+        }
+        gateway_hold_until_ = (now + GATEWAY_HOLD_TIME) | 1;
+    }
+    gateway_last_seen_ = now ? now : 1; // keep 0 as "never seen"
+}
+
 // count read requests from the gateway to other devices, a high rate means it's doing its startup sync
 void EMSESP::gateway_rx_check(const uint8_t * data, const uint8_t length) {
-    if (length < 4 || (data[0] & 0x7F) != EMSdevice::EMS_DEVICE_ID_GATEWAY1 || !(data[1] & 0x80)) {
+    if (length < 2 || (data[0] & 0x7F) != EMSdevice::EMS_DEVICE_ID_GATEWAY1) {
+        return;
+    }
+
+    gateway_note_activity();
+
+    if (length < 4 || !(data[1] & 0x80)) {
         return;
     }
 
diff --git a/src/core/emsesp.h b/src/core/emsesp.h
index 6ffcff21d..f1fd94652 100644
--- a/src/core/emsesp.h
+++ b/src/core/emsesp.h
@@ -300,6 +300,7 @@ class EMSESP {
     // hold our Tx while a gateway (K30RF/KM200 on 0x48) is doing its startup sync, see issue #3094
     // a startup sync is 55-250 read requests/min to other devices, normal operation is <10/min
     static void gateway_rx_check(const uint8_t * data, const uint8_t length);
+    static void gateway_note_activity(); // poll or telegram from 0x48 — re-arm hold if it was silent
     static bool gateway_tx_hold();
     static void gateway_tx_hold_start();
 
@@ -310,6 +311,7 @@ class EMSESP {
     static constexpr uint32_t GATEWAY_HOLD_TIME       = 60000;  // keep holding Tx this long after the last busy window
     static constexpr uint32_t GATEWAY_HOLD_MAX        = 600000; // never hold longer than 10 minutes in one go
     static constexpr uint32_t GATEWAY_HOLD_COOLDOWN   = 600000; // after hitting the max, don't hold again for 10 minutes
+    static constexpr uint32_t GATEWAY_SILENCE_MS      = 60000;  // no 0x48 traffic for this long = gone; next sighting re-arms hold
 
     static uint32_t gateway_hold_until_;
     static uint32_t gateway_hold_start_;
@@ -318,6 +320,7 @@ class EMSESP {
     static uint8_t  gateway_window_count_;
     static uint32_t gateway_fast_start_;
     static uint8_t  gateway_fast_count_;
+    static uint32_t gateway_last_seen_; // last poll or telegram from 0x48
     static uint8_t  last_version_request_src_;
     static uint32_t last_version_request_time_;
 #endif