New failure reason - PHY request fail (unsupported configuration)

ble/src/main/java/no/nordicsemi/android/ble/BleManagerHandler.java

@@ -180,6 +180,11 @@ abstract class BleManagerHandler extends RequestHandler {
 	 * Current connection parameters. Those values are only available starting from Android Oreo.
 	 */
 	private int interval, latency, timeout;
+	/**
+	 * Samsung S8 with Android 9 fails to reconnect to devices requesting PHY LE 2M just after
+	 * connection. Workaround would be to disable PHY LE 2M on the device side.
+	 */
+	private boolean earlyPhyLe2MRequest;
 	/**
 	 * Last received battery value or -1 if value wasn't received.
 	 *
@@ -753,6 +758,7 @@ private boolean internalConnect(@NonNull final BluetoothDevice device,
 			postConnectionStateChange(o -> o.onDeviceConnecting(device));
 		}
 		connectionTime = SystemClock.elapsedRealtime();
+		earlyPhyLe2MRequest = false;
 		if (Build.VERSION.SDK_INT > Build.VERSION_CODES.O) {
 			// connectRequest will never be null here.
 			final int preferredPhy = connectRequest.getPreferredPhy();
@@ -2301,7 +2307,10 @@ public void onConnectionStateChange(@NonNull final BluetoothGatt gatt,
 					// ...because the next method sets them to false.
 
 					// notifyDeviceDisconnected(...) may call close()
-					if (timeout) {
+
+					if (status == GattError.GATT_CONN_TIMEOUT && earlyPhyLe2MRequest) {
+						notifyDeviceDisconnected(gatt.getDevice(), ConnectionObserver.REASON_UNSUPPORTED_CONFIGURATION);
+					} else if (timeout) {
 						notifyDeviceDisconnected(gatt.getDevice(), ConnectionObserver.REASON_TIMEOUT);
 					} else if (notSupported) {
 						notifyDeviceDisconnected(gatt.getDevice(), ConnectionObserver.REASON_NOT_SUPPORTED);
@@ -2332,7 +2341,9 @@ public void onConnectionStateChange(@NonNull final BluetoothGatt gatt,
 					}
 					if (cr != null) {
 						int reason;
-						if (notSupported)
+						if (status == GattError.GATT_CONN_TIMEOUT && earlyPhyLe2MRequest)
+							reason = FailCallback.REASON_UNSUPPORTED_CONFIGURATION;
+						else if (notSupported)
 							reason = FailCallback.REASON_DEVICE_NOT_SUPPORTED;
 						else if (status == BluetoothGatt.GATT_SUCCESS)
 							reason = FailCallback.REASON_DEVICE_DISCONNECTED;
@@ -2948,6 +2959,9 @@ public void onPhyUpdate(@NonNull final BluetoothGatt gatt,
 				log(Log.INFO, () ->
 						"PHY updated (TX: " + ParserUtils.phyToString(txPhy) +
 						", RX: " + ParserUtils.phyToString(rxPhy) + ")");
+				// Samsung S8 fails to reconnect when PHY LE 2M request is sent before service discovery.
+				earlyPhyLe2MRequest = earlyPhyLe2MRequest ||
+						(txPhy == BluetoothDevice.PHY_LE_2M && !servicesDiscovered);
 				if (request instanceof final PhyRequest pr) {
 					pr.notifyPhyChanged(gatt.getDevice(), txPhy, rxPhy);
 					pr.notifySuccess(gatt.getDevice());

ble/src/main/java/no/nordicsemi/android/ble/callback/FailCallback.java

@@ -23,19 +23,37 @@
 package no.nordicsemi.android.ble.callback;
 
 import android.bluetooth.BluetoothDevice;
+import android.bluetooth.BluetoothGatt;
+import no.nordicsemi.android.ble.BleManager;
 
 import androidx.annotation.NonNull;
 
 @FunctionalInterface
 public interface FailCallback {
 	int REASON_DEVICE_DISCONNECTED = -1;
+	/**
+	 * Returned when the {@link BleManager#isRequiredServiceSupported(BluetoothGatt)}
+	 * returns false, that is when at least required GATT service was not discovered
+	 * on the connected device.
+	 */
 	int REASON_DEVICE_NOT_SUPPORTED = -2;
 	int REASON_NULL_ATTRIBUTE = -3;
 	int REASON_REQUEST_FAILED = -4;
 	int REASON_TIMEOUT = -5;
 	int REASON_VALIDATION = -6;
 	int REASON_CANCELLED = -7;
 	int REASON_NOT_ENABLED = -8;
+	/**
+	 * The Android device is unable to reconnect to the peripheral because of internal failure.
+	 * Most probably it cannot respond properly to PHY LE 2M update procedure, causing the
+	 * remote device to terminate the connection.
+	 * <p>
+	 * Try disabling PHY LE 2M on the peripheral side, or update the Android version.
+	 * If that's not possible, the connection to your device may not work on the given
+	 * Android device at all. If the device is bonded, try removing bonding and connect,
+	 * but this seems to fix the problem only before a new bond is created.
+	 */
+	int REASON_UNSUPPORTED_CONFIGURATION = -9;
 	int REASON_BLUETOOTH_DISABLED = -100;
 
 	/**
@@ -47,7 +65,8 @@ public interface FailCallback {
 	 *               {@link #REASON_DEVICE_DISCONNECTED}, {@link #REASON_TIMEOUT},
 	 *               {@link #REASON_DEVICE_NOT_SUPPORTED} (only for Connect request),
 	 *               {@link #REASON_BLUETOOTH_DISABLED}, {@link #REASON_NULL_ATTRIBUTE},
-	 *               {@link #REASON_VALIDATION}, {@link #REASON_CANCELLED}, {@link #REASON_NOT_ENABLED}
+	 *               {@link #REASON_VALIDATION}, {@link #REASON_CANCELLED}, {@link #REASON_NOT_ENABLED},
+	 *               {@link #REASON_UNSUPPORTED_CONFIGURATION},
 	 *               or {@link #REASON_REQUEST_FAILED} (for other reason).
 	 */
 	void onRequestFailed(@NonNull final BluetoothDevice device, final int status);

ble/src/main/java/no/nordicsemi/android/ble/observer/ConnectionObserver.java

@@ -58,6 +58,17 @@ public interface ConnectionObserver {
 	 * or doesn't respond for another reason.
 	 */
 	int REASON_TIMEOUT = 10;
+	/**
+	 * The Android device is unable to reconnect to the peripheral because of internal failure.
+	 * Most probably it cannot respond properly to PHY LE 2M update procedure, causing the
+	 * remote device to terminate the connection.
+	 * <p>
+	 * Try disabling PHY LE 2M on the peripheral side, or update the Android version.
+	 * If that's not possible, the connection to your device may not work on the given
+	 * Android device at all. If the device is bonded, try removing bonding and connect,
+	 * but this seems to fix the problem only before a new bond is created.
+	 */
+	int REASON_UNSUPPORTED_CONFIGURATION = 11;
 
 	/**
 	 * Called when the Android device started connecting to given device.