Allow keyguard dialogs to show on secondary displays.

When the keyguard or a dream is visible, we usually block content
from showing on secondary displays by mirroring the primary display
contents to them.  However, the keyguard may wish to show a
presentation on a secondary display in which case we should not
mirror.

This change adds an exemption for keyguard dialogs when the full
screen is obscured.  The keyguard can then create presentations with
the TYPE_KEYGUARD_DIALOG window type in order to show special
content on other displays selectively.

The old code used to cause all secondary displays to mirror, which
isn't quite what we want.

Bug: 11257292
Change-Id: I55429002b2233ae25fe80db149636d6f41f2a112

1 files changed, 35 insertions, 36 deletions

diff --git a/services/java/com/android/server/wm/WindowManagerService.java b/services/java/com/android/server/wm/WindowManagerService.java
index e1e9f5c..55b0b3a 100644
--- a/services/java/com/android/server/wm/WindowManagerService.java
+++ b/services/java/com/android/server/wm/WindowManagerService.java
@@ -578,10 +578,13 @@ public class WindowManagerService extends IWindowManager.Stub
         private boolean mUpdateRotation = false;
         boolean mWallpaperActionPending = false;
 
-        private static final int DISPLAY_CONTENT_UNKNOWN = 0;
-        private static final int DISPLAY_CONTENT_MIRROR = 1;
-        private static final int DISPLAY_CONTENT_UNIQUE = 2;
-        private int mDisplayHasContent = DISPLAY_CONTENT_UNKNOWN;
+        // Set to true when the display contains content to show the user.
+        // When false, the display manager may choose to mirror or blank the display.
+        boolean mDisplayHasContent = false;
+
+        // Only set while traversing the default display based on its content.
+        // Affects the behavior of mirroring on secondary displays.
+        boolean mObscureApplicationContentOnSecondaryDisplays = false;
     }
     final LayoutFields mInnerFields = new LayoutFields();
 
@@ -8784,6 +8787,14 @@ public class WindowManagerService extends IWindowManager.Stub
         final WindowManager.LayoutParams attrs = w.mAttrs;
         final int attrFlags = attrs.flags;
         final boolean canBeSeen = w.isDisplayedLw();
+        final boolean opaqueDrawn = canBeSeen && w.isOpaqueDrawn();
+
+        if (opaqueDrawn && w.isFullscreen(innerDw, innerDh)) {
+            // This window completely covers everything behind it,
+            // so we want to leave all of them as undimmed (for
+            // performance reasons).
+            mInnerFields.mObscured = true;
+        }
 
         if (w.mHasSurface) {
             if ((attrFlags&FLAG_KEEP_SCREEN_ON) != 0) {
@@ -8812,22 +8823,24 @@ public class WindowManagerService extends IWindowManager.Stub
             }
 
             if (canBeSeen) {
-                if (type == TYPE_DREAM || type == TYPE_KEYGUARD) {
-                    mInnerFields.mDisplayHasContent = LayoutFields.DISPLAY_CONTENT_MIRROR;
-                } else if (mInnerFields.mDisplayHasContent
-                        == LayoutFields.DISPLAY_CONTENT_UNKNOWN) {
-                    mInnerFields.mDisplayHasContent = LayoutFields.DISPLAY_CONTENT_UNIQUE;
+                // This function assumes that the contents of the default display are
+                // processed first before secondary displays.
+                if (w.mDisplayContent.isDefaultDisplay) {
+                    // While a dream or keyguard is showing, obscure ordinary application
+                    // content on secondary displays (by forcibly enabling mirroring unless
+                    // there is other content we want to show) but still allow opaque
+                    // keyguard dialogs to be shown.
+                    if (type == TYPE_DREAM || type == TYPE_KEYGUARD) {
+                        mInnerFields.mObscureApplicationContentOnSecondaryDisplays = true;
+                    }
+                    mInnerFields.mDisplayHasContent = true;
+                } else if (!mInnerFields.mObscureApplicationContentOnSecondaryDisplays
+                        || (mInnerFields.mObscured && type == TYPE_KEYGUARD_DIALOG)) {
+                    // Allow full screen keyguard presentation dialogs to be seen.
+                    mInnerFields.mDisplayHasContent = true;
                 }
             }
         }
-
-        boolean opaqueDrawn = canBeSeen && w.isOpaqueDrawn();
-        if (opaqueDrawn && w.isFullscreen(innerDw, innerDh)) {
-            // This window completely covers everything behind it,
-            // so we want to leave all of them as undimmed (for
-            // performance reasons).
-            mInnerFields.mObscured = true;
-        }
     }
 
     private void handleFlagDimBehind(WindowState w, int innerDw, int innerDh) {
@@ -8905,7 +8918,7 @@ public class WindowManagerService extends IWindowManager.Stub
         mInnerFields.mScreenBrightness = -1;
         mInnerFields.mButtonBrightness = -1;
         mInnerFields.mUserActivityTimeout = -1;
-        mInnerFields.mDisplayHasContent = LayoutFields.DISPLAY_CONTENT_UNKNOWN;
+        mInnerFields.mObscureApplicationContentOnSecondaryDisplays = false;
 
         mTransactionSequence++;
 
@@ -8940,10 +8953,8 @@ public class WindowManagerService extends IWindowManager.Stub
                 final int innerDh = displayInfo.appHeight;
                 final boolean isDefaultDisplay = (displayId == Display.DEFAULT_DISPLAY);
 
-                // Reset for each display unless we are forcing mirroring.
-                if (mInnerFields.mDisplayHasContent != LayoutFields.DISPLAY_CONTENT_MIRROR) {
-                    mInnerFields.mDisplayHasContent = LayoutFields.DISPLAY_CONTENT_UNKNOWN;
-                }
+                // Reset for each display.
+                mInnerFields.mDisplayHasContent = false;
 
                 int repeats = 0;
                 do {
@@ -9152,20 +9163,8 @@ public class WindowManagerService extends IWindowManager.Stub
                     updateResizingWindows(w);
                 }
 
-                final boolean hasUniqueContent;
-                switch (mInnerFields.mDisplayHasContent) {
-                    case LayoutFields.DISPLAY_CONTENT_MIRROR:
-                        hasUniqueContent = isDefaultDisplay;
-                        break;
-                    case LayoutFields.DISPLAY_CONTENT_UNIQUE:
-                        hasUniqueContent = true;
-                        break;
-                    case LayoutFields.DISPLAY_CONTENT_UNKNOWN:
-                    default:
-                        hasUniqueContent = false;
-                        break;
-                }
-                mDisplayManagerService.setDisplayHasContent(displayId, hasUniqueContent,
+                mDisplayManagerService.setDisplayHasContent(displayId,
+                        mInnerFields.mDisplayHasContent,
                         true /* inTraversal, must call performTraversalInTrans... below */);
 
                 getDisplayContentLocked(displayId).stopDimmingIfNeeded();