feat: simple global control for backlight/brightness and volume (#6684)

radio/src/mixer.cpp

@@ -1194,12 +1194,6 @@ void evalMixes(uint8_t tick10ms)
   // must be done after mixing because some functions use the inputs/channels values
   // must be done before limits because of the applyLimit function: it checks for safety switches which would be not initialized otherwise
   if (tick10ms) {
-#if defined(AUDIO)
-    requiredSpeakerVolume = g_eeGeneral.speakerVolume + VOLUME_LEVEL_DEF;
-#endif
-  
-    requiredBacklightBright = g_eeGeneral.getBrightness();
-
     if (radioGFEnabled()) {
       evalFunctions(g_eeGeneral.customFn, globalFunctionsContext);
     } else {
@@ -1217,6 +1211,24 @@ void evalMixes(uint8_t tick10ms)
       }
     }
 #endif
+
+#if defined(AUDIO)
+    if (!isFunctionActive(FUNCTION_VOLUME)) {
+      if (g_eeGeneral.volumeSrc) {
+        calcVolumeValue(g_eeGeneral.volumeSrc);
+      } else {
+        requiredSpeakerVolume = g_eeGeneral.speakerVolume + VOLUME_LEVEL_DEF;
+      }
+    }
+#endif
+
+    if (!isFunctionActive(FUNCTION_BACKLIGHT)) {
+      if (g_eeGeneral.backlightSrc) {
+        calcBacklightValue(g_eeGeneral.backlightSrc);
+      } else {
+        requiredBacklightBright = g_eeGeneral.getBrightness();
+      }
+    }  
   }
 
   //========== LIMITS ===============