Add powerlimits to reconfigured radio settings as well as init settings. (#10025)

* Add powerlimits to reconfigured radio settings as well as init settings.

* Refactor preamble length handling for wide LoRa configurations

* Moved the preamble setting to the main class and made the references static

src/graphics/draw/MenuHandler.cpp

@@ -163,9 +163,11 @@ void menuHandler::LoraRegionPicker(uint32_t duration)
 
             // Guard: without a reboot, reconfigure() applies the region directly.
             // Reject LORA_24 on sub-GHz-only hardware — getRadio() used to catch this post-reboot.
+            // TODO: change this to either use the validateLoraConfig() logic or at least check the region for wideLora
+            // rather than a hardcoded check for LORA_24.
             if (selectedRegion == meshtastic_Config_LoRaConfig_RegionCode_LORA_24 &&
                 !(RadioLibInterface::instance && RadioLibInterface::instance->wideLora())) {
-                LOG_WARN("Radio hardware does not support 2.4 GHz; ignoring LORA_24 selection");
+                LOG_WARN("Radio hardware does not support 2.4 GHz; ignoring region selection");
                 return;
             }
 

src/mesh/LR11x0Interface.cpp

@@ -71,12 +71,10 @@ template <typename T> bool LR11x0Interface<T>::init()
 
     RadioLibInterface::init();
 
-    limitPower(LR1110_MAX_POWER);
-
-    if ((power > LR1120_MAX_POWER) &&
-        (config.lora.region == meshtastic_Config_LoRaConfig_RegionCode_LORA_24)) { // clamp again if wide freq range
-        power = LR1120_MAX_POWER;
-        preambleLength = 12; // 12 is the default for operation above 2GHz
+    if (config.lora.region == meshtastic_Config_LoRaConfig_RegionCode_LORA_24) { // clamp if wide freq range
+        limitPower(LR1120_MAX_POWER);
+    } else {
+        limitPower(LR1110_MAX_POWER); // default clamp for non-wide freq range
     }
 
 #ifdef LR11X0_RF_SWITCH_SUBGHZ
@@ -177,6 +175,12 @@ template <typename T> bool LR11x0Interface<T>::reconfigure()
     err = lora.setSyncWord(syncWord);
     assert(err == RADIOLIB_ERR_NONE);
 
+    if (config.lora.region == meshtastic_Config_LoRaConfig_RegionCode_LORA_24) { // clamp if wide freq range
+        limitPower(LR1120_MAX_POWER);
+    } else {
+        limitPower(LR1110_MAX_POWER); // default clamp for non-wide freq range
+    }
+
     err = lora.setPreambleLength(preambleLength);
     assert(err == RADIOLIB_ERR_NONE);
 
@@ -184,11 +188,6 @@ template <typename T> bool LR11x0Interface<T>::reconfigure()
     if (err != RADIOLIB_ERR_NONE)
         RECORD_CRITICALERROR(meshtastic_CriticalErrorCode_INVALID_RADIO_SETTING);
 
-    if (power > LR1110_MAX_POWER) // This chip has lower power limits than some
-        power = LR1110_MAX_POWER;
-    if ((power > LR1120_MAX_POWER) && (config.lora.region == meshtastic_Config_LoRaConfig_RegionCode_LORA_24)) // 2.4G power limit
-        power = LR1120_MAX_POWER;
-
     err = lora.setOutputPower(power);
     assert(err == RADIOLIB_ERR_NONE);
 

src/mesh/RF95Interface.cpp

@@ -240,8 +240,7 @@ bool RF95Interface::reconfigure()
     if (err != RADIOLIB_ERR_NONE)
         RECORD_CRITICALERROR(meshtastic_CriticalErrorCode_INVALID_RADIO_SETTING);
 
-    if (power > RF95_MAX_POWER) // This chip has lower power limits than some
-        power = RF95_MAX_POWER;
+    limitPower(RF95_MAX_POWER);
 
 #ifdef USE_RF95_RFO
     err = lora->setOutputPower(power, true);

src/mesh/RadioInterface.cpp

@@ -1038,6 +1038,13 @@ void RadioInterface::applyModemConfig()
     saveFreq(freq + loraConfig.frequency_offset);
     const char *channelName = channels.getName(channels.getPrimaryIndex());
 
+    if (newRegion->wideLora) {                          // clamp if wide freq range
+        preambleLength = wideLoraPreambleLengthDefault; // 12 is the default for operation above 2GHz
+    } else {
+        preambleLength =
+            preambleLengthDefault; // 8 is default, but we use longer to increase the amount of sleep time when receiving
+    }
+
     slotTimeMsec = computeSlotTimeMsec();
     preambleTimeMsec = preambleLength * (pow_of_2(sf) / bw);
 

src/mesh/RadioInterface.h

@@ -92,15 +92,20 @@ class RadioInterface
     uint8_t sf = 9;
     uint8_t cr = 5;
 
-    const uint8_t NUM_SYM_CAD = 2;       // Number of symbols used for CAD, 2 is the default since RadioLib 6.3.0 as per AN1200.48
-    const uint8_t NUM_SYM_CAD_24GHZ = 4; // Number of symbols used for CAD in 2.4 GHz, 4 is recommended in AN1200.22 of SX1280
+    static constexpr uint8_t NUM_SYM_CAD =
+        2; // Number of symbols used for CAD, 2 is the default since RadioLib 6.3.0 as per AN1200.48
+    static constexpr uint8_t NUM_SYM_CAD_24GHZ =
+        4; // Number of symbols used for CAD in 2.4 GHz, 4 is recommended in AN1200.22 of SX1280
     uint32_t slotTimeMsec = computeSlotTimeMsec();
-    uint16_t preambleLength = 16;    // 8 is default, but we use longer to increase the amount of sleep time when receiving
-    uint32_t preambleTimeMsec = 165; // calculated on startup, this is the default for LongFast
-    const uint32_t PROCESSING_TIME_MSEC =
-        4500;                // time to construct, process and construct a packet again (empirically determined)
-    const uint8_t CWmin = 3; // minimum CWsize
-    const uint8_t CWmax = 8; // maximum CWsize
+    uint16_t preambleLength = 16; // 8 is default, but we use longer to increase the amount of sleep time when receiving
+    static constexpr uint16_t preambleLengthDefault =
+        16; // 8 is default, but we use longer to increase the amount of sleep time when receiving
+    static constexpr uint16_t wideLoraPreambleLengthDefault = 12; // 12 is default for wide Lora
+    uint32_t preambleTimeMsec = 165;                              // calculated on startup, this is the default for LongFast
+    static constexpr uint32_t PROCESSING_TIME_MSEC =
+        4500;                           // time to construct, process and construct a packet again (empirically determined)
+    static constexpr uint8_t CWmin = 3; // minimum CWsize
+    static constexpr uint8_t CWmax = 8; // maximum CWsize
 
     meshtastic_MeshPacket *sendingPacket = NULL; // The packet we are currently sending
     uint32_t lastTxStart = 0L;

src/mesh/SX126xInterface.cpp

@@ -245,8 +245,10 @@ template <typename T> bool SX126xInterface<T>::reconfigure()
     if (err != RADIOLIB_ERR_NONE)
         RECORD_CRITICALERROR(meshtastic_CriticalErrorCode_INVALID_RADIO_SETTING);
 
-    if (power > SX126X_MAX_POWER) // This chip has lower power limits than some
-        power = SX126X_MAX_POWER;
+    limitPower(SX126X_MAX_POWER);
+    // Make sure we reach the minimum power supported to turn the chip on (-9dBm)
+    if (power < -9)
+        power = -9;
 
     err = lora.setOutputPower(power);
     if (err != RADIOLIB_ERR_NONE)

src/mesh/SX128xInterface.cpp

@@ -144,8 +144,7 @@ template <typename T> bool SX128xInterface<T>::reconfigure()
     if (err != RADIOLIB_ERR_NONE)
         RECORD_CRITICALERROR(meshtastic_CriticalErrorCode_INVALID_RADIO_SETTING);
 
-    if (power > SX128X_MAX_POWER) // This chip has lower power limits than some
-        power = SX128X_MAX_POWER;
+    limitPower(SX128X_MAX_POWER);
 
     err = lora.setOutputPower(power);
     if (err != RADIOLIB_ERR_NONE)