usb-serial-for-android: Use wakelock

Android takes some pretty hard measures to save power, including
shutting down the CPU. Since this can interfer with the download from an
usb serial device, we now use a wakelock to keep the CPU running during
download.

Signed-off-by: Christof Arnosti <charno@charno.ch>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/android-mobile/src/org/subsurfacedivelog/mobile/AndroidSerial.java b/android-mobile/src/org/subsurfacedivelog/mobile/AndroidSerial.java
index fa26f065e..c31e79786 100644
--- a/android-mobile/src/org/subsurfacedivelog/mobile/AndroidSerial.java
+++ b/android-mobile/src/org/subsurfacedivelog/mobile/AndroidSerial.java
@@ -5,6 +5,8 @@ import com.hoho.android.usbserial.driver.*;
 import android.hardware.usb.UsbDeviceConnection;
 import android.hardware.usb.UsbManager;
 import android.hardware.usb.UsbDevice;
+import android.os.PowerManager;
+import android.os.PowerManager.WakeLock;
 
 import android.content.Context;
 import android.util.Log;
@@ -69,6 +71,7 @@ public class AndroidSerial {
 	private UsbSerialPort usbSerialPort;
 	private int timeout = 0;
 	private LinkedList<Byte> readBuffer = new LinkedList<Byte>();
+	private WakeLock wakeLock = null;
 
 	private static String printQueue(LinkedList<Byte> readBuffer)
 	{
@@ -83,6 +86,10 @@ public class AndroidSerial {
 	private AndroidSerial(UsbSerialPort usbSerialPort)
 	{
 		this.usbSerialPort = usbSerialPort;
+
+		PowerManager powerManager = (PowerManager) SubsurfaceMobileActivity.getAppContext().getSystemService(Context.POWER_SERVICE);
+		wakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "Subsurface::AndroidSerialWakelock");
+		wakeLock.acquire();
 	}
 
 	public static AndroidSerial open_android_serial(UsbDevice usbDevice, String driverClassName)
@@ -320,6 +327,8 @@ public class AndroidSerial {
 		Log.d(TAG, "in " + Thread.currentThread().getStackTrace()[2].getMethodName());
 		try {
 			usbSerialPort.close();
+			if(wakeLock != null)
+				wakeLock.release();
 			return AndroidSerial.DC_STATUS_SUCCESS;
 		} catch (Exception e) {
 			Log.e(TAG, "Error in " + Thread.currentThread().getStackTrace()[2].getMethodName(), e);