부팅 시 serial packet이 전송되지 않는 버그 수정

app/src/main/java/com/laseroptek/raman/ui/MainActivity.kt

@@ -260,9 +260,11 @@ class MainActivity : ComponentActivity() {
                     // This prevents serial interrupts from stealing CPU during the first frame.
                     delay(200)
 
-                    vm.txPacketOnce()
-
+                    // IMPORTANT:
+                    // rxPacketLoop() starts serial open() asynchronously.
+                    // Start RX first so txPacketOnce() is less likely to run before FD is ready.
                     vm.rxPacketLoop()
+                    vm.txPacketOnce()
                     vm.txPacketLoop()
 
                     Timber.d("System fully operational.")

app/src/main/java/com/laseroptek/raman/ui/screens/main/MainViewModel.kt

@@ -814,24 +814,47 @@ class MainViewModel @Inject constructor(
     }
 
     fun txPacketOnce() {
-        // viewModel init 으로 이동. 필요.
-        // 경고 정보 조회 (주기적 heart beat)
-        // repeatOnLifecycle은 Activity가 포그라운드에 있을 때로 한정지어, 특정 Lifecycle이 Trigger 되었을 때 동작하도록 만드는 block 임.
+        viewModelScope.launch(dispatcherProvider.io) {
+            // txPacketOnce is called during app startup.
+            // Because serial open() is started in rxPacketLoop() asynchronously,
+            // FD can still be -1 here (startup race). Wait briefly before first TX burst.
+            if (!waitUntilSerialReady()) {
+                Timber.e("txPacketOnce skipped: serial port is not ready (fd=%d)", serialPortRepository.getFD())
+                return@launch
+            }
 
-        // tx Version Read
-        txPacket(READ_WRITE.READ, CMD.VERSION, byteArrayOf(0x41.toByte()))
+            // viewModel init 으로 이동. 필요.
+            // 경고 정보 조회 (주기적 heart beat)
+            // repeatOnLifecycle은 Activity가 포그라운드에 있을 때로 한정지어, 특정 Lifecycle이 Trigger 되었을 때 동작하도록 만드는 block 임.
 
-        // tx Q-Switch Write
-        txPacket(READ_WRITE.WRITE, CMD.Q_SWITCH, qSwitch.value)
+            // tx Version Read
+            txPacket(READ_WRITE.READ, CMD.VERSION, byteArrayOf(0x41.toByte()))
 
-        // tx Guide Beam Write
-        txPacket(READ_WRITE.WRITE, CMD.GUIDE_BEAM, GuideBeam(value = getGuideBeamTxValue()))
+            // tx Q-Switch Write
+            txPacket(READ_WRITE.WRITE, CMD.Q_SWITCH, qSwitch.value)
 
-        // tx DCD_GAS Write (DEFAULT VALUE)
-        txPacket(READ_WRITE.WRITE, CMD.DCD_GAS, dcdGas.value.copy(status = 0x50))
+            // tx Guide Beam Write
+            txPacket(READ_WRITE.WRITE, CMD.GUIDE_BEAM, GuideBeam(value = getGuideBeamTxValue()))
 
-        // tx SPRAY_DCD Write (DEFAULT VALUE)
-        txPacket(READ_WRITE.WRITE, CMD.SPRAY_DCD, sprayDcd.value)
+            // tx DCD_GAS Write (DEFAULT VALUE)
+            txPacket(READ_WRITE.WRITE, CMD.DCD_GAS, dcdGas.value.copy(status = 0x50))
+
+            // tx SPRAY_DCD Write (DEFAULT VALUE)
+            txPacket(READ_WRITE.WRITE, CMD.SPRAY_DCD, sprayDcd.value)
+        }
+    }
+
+    private suspend fun waitUntilSerialReady(
+        timeoutMillis: Long = 2000L,
+        pollIntervalMillis: Long = 20L
+    ): Boolean {
+        // Poll FD until open() completes, with a bounded timeout to avoid blocking forever.
+        val start = System.currentTimeMillis()
+        while (System.currentTimeMillis() - start < timeoutMillis) {
+            if (serialPortRepository.getFD() != -1) return true
+            delay(pollIntervalMillis)
+        }
+        return serialPortRepository.getFD() != -1
     }
 
     // Guide Beam step mapping (0~10)