UsbManager: document that passing null setCurrentFunction restores default function

Change-Id: I4340b336f3e91b3b8242f2a66c34a7a7f5c3021f
Signed-off-by: Mike Lockwood <lockwood@android.com>

2 files changed, 4 insertions, 6 deletions

diff --git a/core/java/android/hardware/usb/UsbManager.java b/core/java/android/hardware/usb/UsbManager.java
index 67d200c..b548623 100644
--- a/core/java/android/hardware/usb/UsbManager.java
+++ b/core/java/android/hardware/usb/UsbManager.java
@@ -409,9 +409,10 @@ public class UsbManager {
 
     /**
      * Sets the current USB function.
+     * If function is null, then the current function is set to the default function.
      *
-     * @param function name of the USB function
-     * @param makeDefault true if this should be set as the default
+     * @param function name of the USB function, or null to restore the default function
+     * @param makeDefault true if the function should be set as the new default function
      *
      * {@hide}
      */
diff --git a/services/java/com/android/server/usb/UsbDeviceManager.java b/services/java/com/android/server/usb/UsbDeviceManager.java
index 3139798..c80cd0a 100644
--- a/services/java/com/android/server/usb/UsbDeviceManager.java
+++ b/services/java/com/android/server/usb/UsbDeviceManager.java
@@ -473,10 +473,7 @@ public class UsbDeviceManager {
                 case MSG_SET_CURRENT_FUNCTION:
                     String function = (String)msg.obj;
                     boolean makeDefault = (msg.arg1 == 1);
-                    if (makeDefault) {
-                        if (function == null) {
-                            throw new NullPointerException();
-                        }
+                    if (function != null && makeDefault) {
                         if (mAdbEnabled) {
                             function = addFunction(function, UsbManager.USB_FUNCTION_ADB);
                         }