Stop wifi display discovery when no longer needed.android-4.4.2_r2.0.1android-4.4.2_r2android-4.4.2_r1.0.1android-4.4.2_r1android-4.4.1_r1.0.1android-4.4.1_r1kitkat-mr1.1-releasekitkat-mr1-release

Keep track of how many clients are requesting scans and scan
continuously until all of them are gone then explicitly terminate the
scan instead of letting it time out as before.

Suspend wifi display scans while connecting or connected to a remote
display.  This is handled by both the display manager and media router
since neither has complete information about what is happening.
Much of this code will no longer be needed once wifi display support
is integrated directly into the media router service.

Ensure that we don't attempt to scan or connect to wifi displays
while the wifi display feature is off.

Infer when a connection attempt fails and unselect the wifi display
route automatically so it doesn't appear to be connecting forever.

Fix issues around correctly canceling and retrying connection attempts.
Often we would cancel but not retry.

Improved connection reliability somewhat.  It seems that discovery must
already be in progress in order for a connection attempt to succeed.

Ensure QuickSettings uses exactly the same logic as the MediaRouteButton
to determine when the remote display tile should be made visible.

Bug: 11717053
Change-Id: I18afc977b0e8c26204b8c96adaa79f05225f7b6e

8 files changed, 318 insertions, 125 deletions

diff --git a/core/java/android/hardware/display/DisplayManager.java b/core/java/android/hardware/display/DisplayManager.java
index d5208d97bd41..093e0e9270ff 100644
--- a/core/java/android/hardware/display/DisplayManager.java
+++ b/core/java/android/hardware/display/DisplayManager.java
@@ -297,16 +297,31 @@ public final class DisplayManager {
     }
 
     /**
-     * Initiates a fresh scan of availble Wifi displays.
+     * Starts scanning for available Wifi displays.
      * The results are sent as a {@link #ACTION_WIFI_DISPLAY_STATUS_CHANGED} broadcast.
      * <p>
+     * Calls to this method nest and must be matched by an equal number of calls to
+     * {@link #stopWifiDisplayScan()}.
+     * </p><p>
+     * Requires {@link android.Manifest.permission#CONFIGURE_WIFI_DISPLAY}.
+     * </p>
+     *
+     * @hide
+     */
+    public void startWifiDisplayScan() {
+        mGlobal.startWifiDisplayScan();
+    }
+
+    /**
+     * Stops scanning for available Wifi displays.
+     * <p>
      * Requires {@link android.Manifest.permission#CONFIGURE_WIFI_DISPLAY}.
      * </p>
      *
      * @hide
      */
-    public void scanWifiDisplays() {
-        mGlobal.scanWifiDisplays();
+    public void stopWifiDisplayScan() {
+        mGlobal.stopWifiDisplayScan();
     }
 
     /**
diff --git a/core/java/android/hardware/display/DisplayManagerGlobal.java b/core/java/android/hardware/display/DisplayManagerGlobal.java
index 936a0867fd83..34174301ac8e 100644
--- a/core/java/android/hardware/display/DisplayManagerGlobal.java
+++ b/core/java/android/hardware/display/DisplayManagerGlobal.java
@@ -72,6 +72,8 @@ public final class DisplayManagerGlobal {
     private final SparseArray<DisplayInfo> mDisplayInfoCache = new SparseArray<DisplayInfo>();
     private int[] mDisplayIdCache;
 
+    private int mWifiDisplayScanNestCount;
+
     private DisplayManagerGlobal(IDisplayManager dm) {
         mDm = dm;
     }
@@ -267,11 +269,32 @@ public final class DisplayManagerGlobal {
         }
     }
 
-    public void scanWifiDisplays() {
-        try {
-            mDm.scanWifiDisplays();
-        } catch (RemoteException ex) {
-            Log.e(TAG, "Failed to scan for Wifi displays.", ex);
+    public void startWifiDisplayScan() {
+        synchronized (mLock) {
+            if (mWifiDisplayScanNestCount++ == 0) {
+                registerCallbackIfNeededLocked();
+                try {
+                    mDm.startWifiDisplayScan();
+                } catch (RemoteException ex) {
+                    Log.e(TAG, "Failed to scan for Wifi displays.", ex);
+                }
+            }
+        }
+    }
+
+    public void stopWifiDisplayScan() {
+        synchronized (mLock) {
+            if (--mWifiDisplayScanNestCount == 0) {
+                try {
+                    mDm.stopWifiDisplayScan();
+                } catch (RemoteException ex) {
+                    Log.e(TAG, "Failed to scan for Wifi displays.", ex);
+                }
+            } else if (mWifiDisplayScanNestCount < 0) {
+                Log.wtf(TAG, "Wifi display scan nest count became negative: "
+                        + mWifiDisplayScanNestCount);
+                mWifiDisplayScanNestCount = 0;
+            }
         }
     }
 
diff --git a/core/java/android/hardware/display/IDisplayManager.aidl b/core/java/android/hardware/display/IDisplayManager.aidl
index 6b2c887639bd..68eb13fb6d58 100644
--- a/core/java/android/hardware/display/IDisplayManager.aidl
+++ b/core/java/android/hardware/display/IDisplayManager.aidl
@@ -29,11 +29,14 @@ interface IDisplayManager {
 
     void registerCallback(in IDisplayManagerCallback callback);
 
-    // No permissions required.
-    void scanWifiDisplays();
+    // Requires CONFIGURE_WIFI_DISPLAY permission.
+    // The process must have previously registered a callback.
+    void startWifiDisplayScan();
 
-    // Requires CONFIGURE_WIFI_DISPLAY permission to connect to an unknown device.
-    // No permissions required to connect to a known device.
+    // Requires CONFIGURE_WIFI_DISPLAY permission.
+    void stopWifiDisplayScan();
+
+    // Requires CONFIGURE_WIFI_DISPLAY permission.
     void connectWifiDisplay(String address);
 
     // No permissions required.
@@ -45,6 +48,12 @@ interface IDisplayManager {
     // Requires CONFIGURE_WIFI_DISPLAY permission.
     void forgetWifiDisplay(String address);
 
+    // Requires CONFIGURE_WIFI_DISPLAY permission.
+    void pauseWifiDisplay();
+
+    // Requires CONFIGURE_WIFI_DISPLAY permission.
+    void resumeWifiDisplay();
+
     // No permissions required.
     WifiDisplayStatus getWifiDisplayStatus();
 
@@ -55,10 +64,4 @@ interface IDisplayManager {
 
     // No permissions required but must be same Uid as the creator.
     void releaseVirtualDisplay(in IBinder token);
-
-    // Requires CONFIGURE_WIFI_DISPLAY permission.
-    void pauseWifiDisplay();
-
-    // Requires CONFIGURE_WIFI_DISPLAY permission.
-    void resumeWifiDisplay();
 }
diff --git a/media/java/android/media/MediaRouter.java b/media/java/android/media/MediaRouter.java
index 3f1851d74c34..de202278c40b 100644
--- a/media/java/android/media/MediaRouter.java
+++ b/media/java/android/media/MediaRouter.java
@@ -61,9 +61,6 @@ public class MediaRouter {
     private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);
 
     static class Static implements DisplayManager.DisplayListener {
-        // Time between wifi display scans when actively scanning in milliseconds.
-        private static final int WIFI_DISPLAY_SCAN_INTERVAL = 10000;
-
         final Context mAppContext;
         final Resources mResources;
         final IAudioService mAudioService;
@@ -87,6 +84,7 @@ public class MediaRouter {
 
         final boolean mCanConfigureWifiDisplays;
         boolean mActivelyScanningWifiDisplays;
+        String mPreviousActiveWifiDisplayAddress;
 
         int mDiscoveryRequestRouteTypes;
         boolean mDiscoverRequestActiveScan;
@@ -106,16 +104,6 @@ public class MediaRouter {
             }
         };
 
-        final Runnable mScanWifiDisplays = new Runnable() {
-            @Override
-            public void run() {
-                if (mActivelyScanningWifiDisplays) {
-                    mDisplayService.scanWifiDisplays();
-                    mHandler.postDelayed(this, WIFI_DISPLAY_SCAN_INTERVAL);
-                }
-            }
-        };
-
         Static(Context appContext) {
             mAppContext = appContext;
             mResources = Resources.getSystem();
@@ -279,15 +267,24 @@ public class MediaRouter {
             }
 
             // Update wifi display scanning.
-            if (activeScanWifiDisplay && mCanConfigureWifiDisplays) {
-                if (!mActivelyScanningWifiDisplays) {
-                    mActivelyScanningWifiDisplays = true;
-                    mHandler.post(mScanWifiDisplays);
+            // TODO: All of this should be managed by the media router service.
+            if (mCanConfigureWifiDisplays) {
+                if (mSelectedRoute != null
+                        && mSelectedRoute.matchesTypes(ROUTE_TYPE_REMOTE_DISPLAY)) {
+                    // Don't scan while already connected to a remote display since
+                    // it may interfere with the ongoing transmission.
+                    activeScanWifiDisplay = false;
                 }
-            } else {
-                if (mActivelyScanningWifiDisplays) {
-                    mActivelyScanningWifiDisplays = false;
-                    mHandler.removeCallbacks(mScanWifiDisplays);
+                if (activeScanWifiDisplay) {
+                    if (!mActivelyScanningWifiDisplays) {
+                        mActivelyScanningWifiDisplays = true;
+                        mDisplayService.startWifiDisplayScan();
+                    }
+                } else {
+                    if (mActivelyScanningWifiDisplays) {
+                        mActivelyScanningWifiDisplays = false;
+                        mDisplayService.stopWifiDisplayScan();
+                    }
                 }
             }
 
@@ -945,6 +942,9 @@ public class MediaRouter {
             }
             dispatchRouteSelected(types & route.getSupportedTypes(), route);
         }
+
+        // The behavior of active scans may depend on the currently selected route.
+        sStatic.updateDiscoveryRequest();
     }
 
     static void selectDefaultRouteStatic() {
@@ -1291,10 +1291,8 @@ public class MediaRouter {
     }
 
     static void updateWifiDisplayStatus(WifiDisplayStatus status) {
-        boolean wantScan = false;
         WifiDisplay[] displays;
         WifiDisplay activeDisplay;
-
         if (status.getFeatureState() == WifiDisplayStatus.FEATURE_STATE_ON) {
             displays = status.getDisplays();
             activeDisplay = status.getActiveDisplay();
@@ -1314,6 +1312,8 @@ public class MediaRouter {
             displays = WifiDisplay.EMPTY_ARRAY;
             activeDisplay = null;
         }
+        String activeDisplayAddress = activeDisplay != null ?
+                activeDisplay.getDeviceAddress() : null;
 
         // Add or update routes.
         for (int i = 0; i < displays.length; i++) {
@@ -1323,9 +1323,11 @@ public class MediaRouter {
                 if (route == null) {
                     route = makeWifiDisplayRoute(d, status);
                     addRouteStatic(route);
-                    wantScan = true;
                 } else {
-                    updateWifiDisplayRoute(route, d, status);
+                    String address = d.getDeviceAddress();
+                    boolean disconnected = !address.equals(activeDisplayAddress)
+                            && address.equals(sStatic.mPreviousActiveWifiDisplayAddress);
+                    updateWifiDisplayRoute(route, d, status, disconnected);
                 }
                 if (d.equals(activeDisplay)) {
                     selectRouteStatic(route.getSupportedTypes(), route, false);
@@ -1343,6 +1345,10 @@ public class MediaRouter {
                 }
             }
         }
+
+        // Remember the current active wifi display address so that we can infer disconnections.
+        // TODO: This hack will go away once all of this is moved into the media router service.
+        sStatic.mPreviousActiveWifiDisplayAddress = activeDisplayAddress;
     }
 
     private static boolean shouldShowWifiDisplay(WifiDisplay d, WifiDisplay activeDisplay) {
@@ -1400,7 +1406,8 @@ public class MediaRouter {
     }
 
     private static void updateWifiDisplayRoute(
-            RouteInfo route, WifiDisplay display, WifiDisplayStatus wfdStatus) {
+            RouteInfo route, WifiDisplay display, WifiDisplayStatus wfdStatus,
+            boolean disconnected) {
         boolean changed = false;
         final String newName = display.getFriendlyDisplayName();
         if (!route.getName().equals(newName)) {
@@ -1418,7 +1425,7 @@ public class MediaRouter {
             dispatchRouteChanged(route);
         }
 
-        if (!enabled && route.isSelected()) {
+        if ((!enabled || disconnected) && route.isSelected()) {
             // Oops, no longer available. Reselect the default.
             selectDefaultRouteStatic();
         }
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/QuickSettingsModel.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/QuickSettingsModel.java
index e1a20ecedfd4..42201c5a2d98 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/QuickSettingsModel.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/QuickSettingsModel.java
@@ -692,14 +692,8 @@ class QuickSettingsModel implements BluetoothStateChangeCallback,
         } else {
             connectedRoute = null;
             connecting = false;
-            final int count = mMediaRouter.getRouteCount();
-            for (int i = 0; i < count; i++) {
-                MediaRouter.RouteInfo route = mMediaRouter.getRouteAt(i);
-                if (route.matchesTypes(MediaRouter.ROUTE_TYPE_REMOTE_DISPLAY)) {
-                    enabled = true;
-                    break;
-                }
-            }
+            enabled = mMediaRouter.isRouteAvailable(MediaRouter.ROUTE_TYPE_REMOTE_DISPLAY,
+                    MediaRouter.AVAILABILITY_FLAG_IGNORE_DEFAULT_ROUTE);
         }
 
         mRemoteDisplayState.enabled = enabled;
diff --git a/services/java/com/android/server/display/DisplayManagerService.java b/services/java/com/android/server/display/DisplayManagerService.java
index 02f26b375a2a..bcb677fa455f 100644
--- a/services/java/com/android/server/display/DisplayManagerService.java
+++ b/services/java/com/android/server/display/DisplayManagerService.java
@@ -35,6 +35,7 @@ import android.os.RemoteException;
 import android.os.SystemClock;
 import android.os.SystemProperties;
 import android.text.TextUtils;
+import android.util.Log;
 import android.util.Slog;
 import android.util.SparseArray;
 import android.view.Display;
@@ -173,6 +174,9 @@ public final class DisplayManagerService extends IDisplayManager.Stub {
     // The Wifi display adapter, or null if not registered.
     private WifiDisplayAdapter mWifiDisplayAdapter;
 
+    // The number of active wifi display scan requests.
+    private int mWifiDisplayScanRequestCount;
+
     // The virtual display adapter, or null if not registered.
     private VirtualDisplayAdapter mVirtualDisplayAdapter;
 
@@ -458,29 +462,81 @@ public final class DisplayManagerService extends IDisplayManager.Stub {
         }
     }
 
-    private void onCallbackDied(int pid) {
+    private void onCallbackDied(CallbackRecord record) {
         synchronized (mSyncRoot) {
-            mCallbacks.remove(pid);
+            mCallbacks.remove(record.mPid);
+            stopWifiDisplayScanLocked(record);
         }
     }
 
     @Override // Binder call
-    public void scanWifiDisplays() {
+    public void startWifiDisplayScan() {
         mContext.enforceCallingOrSelfPermission(Manifest.permission.CONFIGURE_WIFI_DISPLAY,
-                "Permission required to scan wifi displays");
+                "Permission required to start wifi display scans");
 
+        final int callingPid = Binder.getCallingPid();
         final long token = Binder.clearCallingIdentity();
         try {
             synchronized (mSyncRoot) {
+                CallbackRecord record = mCallbacks.get(callingPid);
+                if (record == null) {
+                    throw new IllegalStateException("The calling process has not "
+                            + "registered an IDisplayManagerCallback.");
+                }
+                startWifiDisplayScanLocked(record);
+            }
+        } finally {
+            Binder.restoreCallingIdentity(token);
+        }
+    }
+
+    private void startWifiDisplayScanLocked(CallbackRecord record) {
+        if (!record.mWifiDisplayScanRequested) {
+            record.mWifiDisplayScanRequested = true;
+            if (mWifiDisplayScanRequestCount++ == 0) {
                 if (mWifiDisplayAdapter != null) {
-                    mWifiDisplayAdapter.requestScanLocked();
+                    mWifiDisplayAdapter.requestStartScanLocked();
                 }
             }
+        }
+    }
+
+    @Override // Binder call
+    public void stopWifiDisplayScan() {
+        mContext.enforceCallingOrSelfPermission(Manifest.permission.CONFIGURE_WIFI_DISPLAY,
+                "Permission required to stop wifi display scans");
+
+        final int callingPid = Binder.getCallingPid();
+        final long token = Binder.clearCallingIdentity();
+        try {
+            synchronized (mSyncRoot) {
+                CallbackRecord record = mCallbacks.get(callingPid);
+                if (record == null) {
+                    throw new IllegalStateException("The calling process has not "
+                            + "registered an IDisplayManagerCallback.");
+                }
+                stopWifiDisplayScanLocked(record);
+            }
         } finally {
             Binder.restoreCallingIdentity(token);
         }
     }
 
+    private void stopWifiDisplayScanLocked(CallbackRecord record) {
+        if (record.mWifiDisplayScanRequested) {
+            record.mWifiDisplayScanRequested = false;
+            if (--mWifiDisplayScanRequestCount == 0) {
+                if (mWifiDisplayAdapter != null) {
+                    mWifiDisplayAdapter.requestStopScanLocked();
+                }
+            } else if (mWifiDisplayScanRequestCount < 0) {
+                Log.wtf(TAG, "mWifiDisplayScanRequestCount became negative: "
+                        + mWifiDisplayScanRequestCount);
+                mWifiDisplayScanRequestCount = 0;
+            }
+        }
+    }
+
     @Override // Binder call
     public void connectWifiDisplay(String address) {
         if (address == null) {
@@ -1107,6 +1163,7 @@ public final class DisplayManagerService extends IDisplayManager.Stub {
             pw.println("  mDefaultViewport=" + mDefaultViewport);
             pw.println("  mExternalTouchViewport=" + mExternalTouchViewport);
             pw.println("  mSingleDisplayDemoMode=" + mSingleDisplayDemoMode);
+            pw.println("  mWifiDisplayScanRequestCount=" + mWifiDisplayScanRequestCount);
 
             IndentingPrintWriter ipw = new IndentingPrintWriter(pw, "    ");
             ipw.increaseIndent();
@@ -1134,6 +1191,15 @@ public final class DisplayManagerService extends IDisplayManager.Stub {
                 pw.println("  Display " + displayId + ":");
                 display.dumpLocked(ipw);
             }
+
+            final int callbackCount = mCallbacks.size();
+            pw.println();
+            pw.println("Callbacks: size=" + callbackCount);
+            for (int i = 0; i < callbackCount; i++) {
+                CallbackRecord callback = mCallbacks.valueAt(i);
+                pw.println("  " + i + ": mPid=" + callback.mPid
+                        + ", mWifiDisplayScanRequested=" + callback.mWifiDisplayScanRequested);
+            }
         }
     }
 
@@ -1234,9 +1300,11 @@ public final class DisplayManagerService extends IDisplayManager.Stub {
     }
 
     private final class CallbackRecord implements DeathRecipient {
-        private final int mPid;
+        public final int mPid;
         private final IDisplayManagerCallback mCallback;
 
+        public boolean mWifiDisplayScanRequested;
+
         public CallbackRecord(int pid, IDisplayManagerCallback callback) {
             mPid = pid;
             mCallback = callback;
@@ -1247,7 +1315,7 @@ public final class DisplayManagerService extends IDisplayManager.Stub {
             if (DEBUG) {
                 Slog.d(TAG, "Display listener for pid " + mPid + " died.");
             }
-            onCallbackDied(mPid);
+            onCallbackDied(this);
         }
 
         public void notifyDisplayEventAsync(int displayId, int event) {
diff --git a/services/java/com/android/server/display/WifiDisplayAdapter.java b/services/java/com/android/server/display/WifiDisplayAdapter.java
index fdef0398078d..cd57941bcc3e 100644
--- a/services/java/com/android/server/display/WifiDisplayAdapter.java
+++ b/services/java/com/android/server/display/WifiDisplayAdapter.java
@@ -127,7 +127,7 @@ final class WifiDisplayAdapter extends DisplayAdapter {
         pw.println("mPendingStatusChangeBroadcast=" + mPendingStatusChangeBroadcast);
         pw.println("mPendingNotificationUpdate=" + mPendingNotificationUpdate);
         pw.println("mSupportsProtectedBuffers=" + mSupportsProtectedBuffers);
-
+ 
         // Try to dump the controller state.
         if (mDisplayController == null) {
             pw.println("mDisplayController=null");
@@ -157,43 +157,49 @@ final class WifiDisplayAdapter extends DisplayAdapter {
         });
     }
 
-    public void requestScanLocked() {
+    public void requestStartScanLocked() {
         if (DEBUG) {
-            Slog.d(TAG, "requestScanLocked");
+            Slog.d(TAG, "requestStartScanLocked");
         }
 
         getHandler().post(new Runnable() {
             @Override
             public void run() {
                 if (mDisplayController != null) {
-                    mDisplayController.requestScan();
+                    mDisplayController.requestStartScan();
                 }
             }
         });
     }
 
-    public void requestConnectLocked(final String address) {
+    public void requestStopScanLocked() {
         if (DEBUG) {
-            Slog.d(TAG, "requestConnectLocked: address=" + address);
+            Slog.d(TAG, "requestStopScanLocked");
         }
 
         getHandler().post(new Runnable() {
             @Override
             public void run() {
                 if (mDisplayController != null) {
-                    mDisplayController.requestConnect(address);
+                    mDisplayController.requestStopScan();
                 }
             }
         });
     }
 
-    private boolean isRememberedDisplayLocked(String address) {
-        for (WifiDisplay display : mRememberedDisplays) {
-            if (display.getDeviceAddress().equals(address)) {
-                return true;
-            }
+    public void requestConnectLocked(final String address) {
+        if (DEBUG) {
+            Slog.d(TAG, "requestConnectLocked: address=" + address);
         }
-        return false;
+
+        getHandler().post(new Runnable() {
+            @Override
+            public void run() {
+                if (mDisplayController != null) {
+                    mDisplayController.requestConnect(address);
+                }
+            }
+        });
     }
 
     public void requestPauseLocked() {
@@ -552,20 +558,20 @@ final class WifiDisplayAdapter extends DisplayAdapter {
         }
 
         @Override
-        public void onScanFinished(WifiDisplay[] availableDisplays) {
+        public void onScanResults(WifiDisplay[] availableDisplays) {
             synchronized (getSyncRoot()) {
                 availableDisplays = mPersistentDataStore.applyWifiDisplayAliases(
                         availableDisplays);
 
-                // check if any of the available displays changed canConnect status
                 boolean changed = !Arrays.equals(mAvailableDisplays, availableDisplays);
+
+                // Check whether any of the available displays changed canConnect status.
                 for (int i = 0; !changed && i<availableDisplays.length; i++) {
                     changed = availableDisplays[i].canConnect()
                             != mAvailableDisplays[i].canConnect();
                 }
 
-                if (mScanState != WifiDisplayStatus.SCAN_STATE_NOT_SCANNING || changed) {
-                    mScanState = WifiDisplayStatus.SCAN_STATE_NOT_SCANNING;
+                if (changed) {
                     mAvailableDisplays = availableDisplays;
                     fixRememberedDisplayNamesFromAvailableDisplaysLocked();
                     updateDisplaysLocked();
@@ -575,6 +581,16 @@ final class WifiDisplayAdapter extends DisplayAdapter {
         }
 
         @Override
+        public void onScanFinished() {
+            synchronized (getSyncRoot()) {
+                if (mScanState != WifiDisplayStatus.SCAN_STATE_NOT_SCANNING) {
+                    mScanState = WifiDisplayStatus.SCAN_STATE_NOT_SCANNING;
+                    scheduleStatusChangedBroadcastLocked();
+                }
+            }
+        }
+
+        @Override
         public void onDisplayConnecting(WifiDisplay display) {
             synchronized (getSyncRoot()) {
                 display = mPersistentDataStore.applyWifiDisplayAlias(display);
diff --git a/services/java/com/android/server/display/WifiDisplayController.java b/services/java/com/android/server/display/WifiDisplayController.java
index b2939fe7e4d4..dbb59b269bf5 100644
--- a/services/java/com/android/server/display/WifiDisplayController.java
+++ b/services/java/com/android/server/display/WifiDisplayController.java
@@ -27,7 +27,6 @@ import android.database.ContentObserver;
 import android.hardware.display.WifiDisplay;
 import android.hardware.display.WifiDisplaySessionInfo;
 import android.hardware.display.WifiDisplayStatus;
-import android.media.AudioManager;
 import android.media.RemoteDisplay;
 import android.net.NetworkInfo;
 import android.net.Uri;
@@ -75,12 +74,19 @@ final class WifiDisplayController implements DumpUtils.Dump {
 
     private static final int DEFAULT_CONTROL_PORT = 7236;
     private static final int MAX_THROUGHPUT = 50;
-    private static final int CONNECTION_TIMEOUT_SECONDS = 60;
+    private static final int CONNECTION_TIMEOUT_SECONDS = 30;
     private static final int RTSP_TIMEOUT_SECONDS = 30;
     private static final int RTSP_TIMEOUT_SECONDS_CERT_MODE = 120;
 
-    private static final int DISCOVER_PEERS_MAX_RETRIES = 10;
-    private static final int DISCOVER_PEERS_RETRY_DELAY_MILLIS = 500;
+    // We repeatedly issue calls to discover peers every so often for a few reasons.
+    // 1. The initial request may fail and need to retried.
+    // 2. Discovery will self-abort after any group is initiated, which may not necessarily
+    //    be what we want to have happen.
+    // 3. Discovery will self-timeout after 2 minutes, whereas we want discovery to
+    //    be occur for as long as a client is requesting it be.
+    // 4. We don't seem to get updated results for displays we've already found until
+    //    we ask to discover again, particularly for the isSessionAvailable() property.
+    private static final int DISCOVER_PEERS_INTERVAL_MILLIS = 10000;
 
     private static final int CONNECT_MAX_RETRIES = 3;
     private static final int CONNECT_RETRY_DELAY_MILLIS = 500;
@@ -103,12 +109,12 @@ final class WifiDisplayController implements DumpUtils.Dump {
     // True if Wifi display is enabled by the user.
     private boolean mWifiDisplayOnSetting;
 
+    // True if a scan was requested independent of whether one is actually in progress.
+    private boolean mScanRequested;
+
     // True if there is a call to discoverPeers in progress.
     private boolean mDiscoverPeersInProgress;
 
-    // Number of discover peers retries remaining.
-    private int mDiscoverPeersRetriesLeft;
-
     // The device to which we want to connect, or null if we want to be disconnected.
     private WifiP2pDevice mDesiredDevice;
 
@@ -209,8 +215,8 @@ final class WifiDisplayController implements DumpUtils.Dump {
         pw.println("mWfdEnabled=" + mWfdEnabled);
         pw.println("mWfdEnabling=" + mWfdEnabling);
         pw.println("mNetworkInfo=" + mNetworkInfo);
+        pw.println("mScanRequested=" + mScanRequested);
         pw.println("mDiscoverPeersInProgress=" + mDiscoverPeersInProgress);
-        pw.println("mDiscoverPeersRetriesLeft=" + mDiscoverPeersRetriesLeft);
         pw.println("mDesiredDevice=" + describeWifiP2pDevice(mDesiredDevice));
         pw.println("mConnectingDisplay=" + describeWifiP2pDevice(mConnectingDevice));
         pw.println("mDisconnectingDisplay=" + describeWifiP2pDevice(mDisconnectingDevice));
@@ -232,8 +238,18 @@ final class WifiDisplayController implements DumpUtils.Dump {
         }
     }
 
-    public void requestScan() {
-        discoverPeers();
+    public void requestStartScan() {
+        if (!mScanRequested) {
+            mScanRequested = true;
+            updateScanState();
+        }
+    }
+
+    public void requestStopScan() {
+        if (mScanRequested) {
+            mScanRequested = false;
+            updateScanState();
+        }
     }
 
     public void requestConnect(String address) {
@@ -282,6 +298,7 @@ final class WifiDisplayController implements DumpUtils.Dump {
                             mWfdEnabling = false;
                             mWfdEnabled = true;
                             reportFeatureState();
+                            updateScanState();
                         }
                     }
 
@@ -318,6 +335,7 @@ final class WifiDisplayController implements DumpUtils.Dump {
             mWfdEnabling = false;
             mWfdEnabled = false;
             reportFeatureState();
+            updateScanState();
             disconnect();
         }
     }
@@ -340,12 +358,29 @@ final class WifiDisplayController implements DumpUtils.Dump {
                 WifiDisplayStatus.FEATURE_STATE_OFF;
     }
 
-    private void discoverPeers() {
-        if (!mDiscoverPeersInProgress) {
-            mDiscoverPeersInProgress = true;
-            mDiscoverPeersRetriesLeft = DISCOVER_PEERS_MAX_RETRIES;
-            handleScanStarted();
-            tryDiscoverPeers();
+    private void updateScanState() {
+        if (mScanRequested && mWfdEnabled && mDesiredDevice == null) {
+            if (!mDiscoverPeersInProgress) {
+                Slog.i(TAG, "Starting Wifi display scan.");
+                mDiscoverPeersInProgress = true;
+                handleScanStarted();
+                tryDiscoverPeers();
+            }
+        } else {
+            if (mDiscoverPeersInProgress) {
+                // Cancel automatic retry right away.
+                mHandler.removeCallbacks(mDiscoverPeers);
+
+                // Defer actually stopping discovery if we have a connection attempt in progress.
+                // The wifi display connection attempt often fails if we are not in discovery
+                // mode.  So we allow discovery to continue until we give up trying to connect.
+                if (mDesiredDevice == null || mDesiredDevice == mConnectedDevice) {
+                    Slog.i(TAG, "Stopping Wifi display scan.");
+                    mDiscoverPeersInProgress = false;
+                    stopPeerDiscovery();
+                    handleScanFinished();
+                }
+            }
         }
     }
 
@@ -357,8 +392,9 @@ final class WifiDisplayController implements DumpUtils.Dump {
                     Slog.d(TAG, "Discover peers succeeded.  Requesting peers now.");
                 }
 
-                mDiscoverPeersInProgress = false;
-                requestPeers();
+                if (mDiscoverPeersInProgress) {
+                    requestPeers();
+                }
             }
 
             @Override
@@ -367,30 +403,28 @@ final class WifiDisplayController implements DumpUtils.Dump {
                     Slog.d(TAG, "Discover peers failed with reason " + reason + ".");
                 }
 
-                if (mDiscoverPeersInProgress) {
-                    if (reason == 0 && mDiscoverPeersRetriesLeft > 0 && mWfdEnabled) {
-                        mHandler.postDelayed(new Runnable() {
-                            @Override
-                            public void run() {
-                                if (mDiscoverPeersInProgress) {
-                                    if (mDiscoverPeersRetriesLeft > 0 && mWfdEnabled) {
-                                        mDiscoverPeersRetriesLeft -= 1;
-                                        if (DEBUG) {
-                                            Slog.d(TAG, "Retrying discovery.  Retries left: "
-                                                    + mDiscoverPeersRetriesLeft);
-                                        }
-                                        tryDiscoverPeers();
-                                    } else {
-                                        handleScanFinished();
-                                        mDiscoverPeersInProgress = false;
-                                    }
-                                }
-                            }
-                        }, DISCOVER_PEERS_RETRY_DELAY_MILLIS);
-                    } else {
-                        handleScanFinished();
-                        mDiscoverPeersInProgress = false;
-                    }
+                // Ignore the error.
+                // We will retry automatically in a little bit.
+            }
+        });
+
+        // Retry discover peers periodically until stopped.
+        mHandler.postDelayed(mDiscoverPeers, DISCOVER_PEERS_INTERVAL_MILLIS);
+    }
+
+    private void stopPeerDiscovery() {
+        mWifiP2pManager.stopPeerDiscovery(mWifiP2pChannel, new ActionListener() {
+            @Override
+            public void onSuccess() {
+                if (DEBUG) {
+                    Slog.d(TAG, "Stop peer discovery succeeded.");
+                }
+            }
+
+            @Override
+            public void onFailure(int reason) {
+                if (DEBUG) {
+                    Slog.d(TAG, "Stop peer discovery failed with reason " + reason + ".");
                 }
             }
         });
@@ -415,7 +449,9 @@ final class WifiDisplayController implements DumpUtils.Dump {
                     }
                 }
 
-                handleScanFinished();
+                if (mDiscoverPeersInProgress) {
+                    handleScanResults();
+                }
             }
         });
     }
@@ -429,7 +465,7 @@ final class WifiDisplayController implements DumpUtils.Dump {
         });
     }
 
-    private void handleScanFinished() {
+    private void handleScanResults() {
         final int count = mAvailableWifiDisplayPeers.size();
         final WifiDisplay[] displays = WifiDisplay.CREATOR.newArray(count);
         for (int i = 0; i < count; i++) {
@@ -441,7 +477,16 @@ final class WifiDisplayController implements DumpUtils.Dump {
         mHandler.post(new Runnable() {
             @Override
             public void run() {
-                mListener.onScanFinished(displays);
+                mListener.onScanResults(displays);
+            }
+        });
+    }
+
+    private void handleScanFinished() {
+        mHandler.post(new Runnable() {
+            @Override
+            public void run() {
+                mListener.onScanFinished();
             }
         });
     }
@@ -484,6 +529,12 @@ final class WifiDisplayController implements DumpUtils.Dump {
             return;
         }
 
+        if (!mWfdEnabled) {
+            Slog.i(TAG, "Ignoring request to connect to Wifi display because the "
+                    +" feature is currently disabled: " + device.deviceName);
+            return;
+        }
+
         mDesiredDevice = device;
         mConnectionRetriesLeft = CONNECT_MAX_RETRIES;
         updateConnection();
@@ -508,6 +559,10 @@ final class WifiDisplayController implements DumpUtils.Dump {
      * connection is established (or not).
      */
     private void updateConnection() {
+        // Step 0. Stop scans if necessary to prevent interference while connected.
+        // Resume scans later when no longer attempting to connect.
+        updateScanState();
+
         // Step 1. Before we try to connect to a new device, tell the system we
         // have disconnected from the old one.
         if (mRemoteDisplay != null && mConnectedDevice != mDesiredDevice) {
@@ -661,7 +716,7 @@ final class WifiDisplayController implements DumpUtils.Dump {
             return; // wait for asynchronous callback
         }
 
-        // Step 6. Listen for incoming connections.
+        // Step 6. Listen for incoming RTSP connection.
         if (mConnectedDevice != null && mRemoteDisplay == null) {
             Inet4Address addr = getInterfaceAddress(mConnectedDeviceGroupInfo);
             if (addr == null) {
@@ -817,7 +872,11 @@ final class WifiDisplayController implements DumpUtils.Dump {
             }
         } else {
             mConnectedDeviceGroupInfo = null;
-            disconnect();
+
+            // Disconnect if we lost the network while connecting or connected to a display.
+            if (mConnectingDevice != null || mConnectedDevice != null) {
+                disconnect();
+            }
 
             // After disconnection for a group, for some reason we have a tendency
             // to get a peer change notification with an empty list of peers.
@@ -828,6 +887,13 @@ final class WifiDisplayController implements DumpUtils.Dump {
         }
     }
 
+    private final Runnable mDiscoverPeers = new Runnable() {
+        @Override
+        public void run() {
+            tryDiscoverPeers();
+        }
+    };
+
     private final Runnable mConnectionTimeout = new Runnable() {
         @Override
         public void run() {
@@ -1033,7 +1099,8 @@ final class WifiDisplayController implements DumpUtils.Dump {
         void onFeatureStateChanged(int featureState);
 
         void onScanStarted();
-        void onScanFinished(WifiDisplay[] availableDisplays);
+        void onScanResults(WifiDisplay[] availableDisplays);
+        void onScanFinished();
 
         void onDisplayConnecting(WifiDisplay display);
         void onDisplayConnectionFailed();