5 files changed, 39 insertions, 4 deletions

diff --git a/java/AndroidManifest.xml.in b/java/AndroidManifest.xml.in
index e79fb4e46e7..f2aede7369c 100644
--- a/java/AndroidManifest.xml.in
+++ b/java/AndroidManifest.xml.in
@@ -77,10 +77,14 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>. -->
                @ANDROID_SHARED_USER_ID@
                android:extractNativeLibs="true">
 
+    <!-- See EmacsSurfaceView.onDraw for why hardware acceleration is
+         disabled.  -->
+
     <activity android:name="org.gnu.emacs.EmacsActivity"
               android:launchMode="singleInstance"
               android:windowSoftInputMode="adjustResize"
               android:exported="true"
+              android:hardwareAccelerated="false"
               android:configChanges="orientation|screenSize|screenLayout|keyboardHidden">
       <intent-filter>
         <action android:name="android.intent.action.MAIN" />
@@ -173,6 +177,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>. -->
     <activity android:name="org.gnu.emacs.EmacsMultitaskActivity"
               android:windowSoftInputMode="adjustResize"
               android:exported="true"
+              android:hardwareAccelerated="false"
               android:configChanges="orientation|screenSize|screenLayout|keyboardHidden"/>
 
     <activity android:autoRemoveFromRecents="true"
diff --git a/java/org/gnu/emacs/EmacsActivity.java b/java/org/gnu/emacs/EmacsActivity.java
index fa9bff39bb0..d7b51388929 100644
--- a/java/org/gnu/emacs/EmacsActivity.java
+++ b/java/org/gnu/emacs/EmacsActivity.java
@@ -70,7 +70,7 @@ public class EmacsActivity extends Activity
   private boolean isFullscreen;
 
   /* The last context menu to be closed.  */
-  private Menu lastClosedMenu;
+  private static Menu lastClosedMenu;
 
   static
   {
diff --git a/java/org/gnu/emacs/EmacsDialog.java b/java/org/gnu/emacs/EmacsDialog.java
index 5f48a9a5f9f..42455ed78f8 100644
--- a/java/org/gnu/emacs/EmacsDialog.java
+++ b/java/org/gnu/emacs/EmacsDialog.java
@@ -152,7 +152,7 @@ public final class EmacsDialog implements DialogInterface.OnDismissListener
   toAlertDialog (Context context)
   {
     AlertDialog dialog;
-    int size, styleId;
+    int size, styleId, flag;
     int[] attrs;
     EmacsButton button;
     EmacsDialogButtonLayout layout;
@@ -160,6 +160,7 @@ public final class EmacsDialog implements DialogInterface.OnDismissListener
     ViewGroup.LayoutParams layoutParams;
     Theme theme;
     TypedArray attributes;
+    Window window;
 
     size = buttons.size ();
     styleId = -1;
@@ -273,6 +274,17 @@ public final class EmacsDialog implements DialogInterface.OnDismissListener
           }
       }
 
+    /* Make sure the dialog is hardware accelerated.  Hardware
+       acceleration is disabled for dialogs by default, because they
+       aren't enabled in EmacsActivity either.  */
+
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB)
+      {
+        flag = WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED;
+        window = dialog.getWindow ();
+        window.addFlags (flag);
+      }
+
     return dialog;
   }
 
diff --git a/java/org/gnu/emacs/EmacsSurfaceView.java b/java/org/gnu/emacs/EmacsSurfaceView.java
index 3f62af4ab99..54fe70e1634 100644
--- a/java/org/gnu/emacs/EmacsSurfaceView.java
+++ b/java/org/gnu/emacs/EmacsSurfaceView.java
@@ -176,7 +176,25 @@ public final class EmacsSurfaceView extends View
   onDraw (Canvas canvas)
   {
     /* Paint the view's bitmap; the bitmap might be recycled right
-       now.  */
+       now.
+
+       Hardware acceleration is disabled in AndroidManifest.xml to
+       prevent Android from uploading the front buffer to the GPU from
+       a separate thread.  This is important for two reasons: first,
+       the GPU command queue uses a massive amount of memory (dozens
+       of MiB) to upload bitmaps to the GPU, regardless of how much of
+       the bitmap has actually changed.
+
+       Secondly, asynchronous texturization leads to race conditions
+       when a buffer swap occurs before the front buffer is fully
+       uploaded to the GPU.  Normally, only slight and tolerable
+       tearing should result from this behavior, but Android does not
+       properly interlock the ``generation ID'' used to avoid
+       texturizing unchanged bitmaps with the bitmap contents,
+       consequentially leading to textures in an incomplete state
+       remaining in use to the GPU if a buffer swap happens between
+       the image data being uploaded and the ``generation ID'' being
+       read.  */
 
     if (frontBuffer != null)
       canvas.drawBitmap (frontBuffer, 0f, 0f, uiThreadPaint);
diff --git a/java/org/gnu/emacs/EmacsWindow.java b/java/org/gnu/emacs/EmacsWindow.java
index 5e45275631b..0e96a8382d0 100644
--- a/java/org/gnu/emacs/EmacsWindow.java
+++ b/java/org/gnu/emacs/EmacsWindow.java
@@ -1377,7 +1377,7 @@ public final class EmacsWindow extends EmacsHandleObject
 
           if (tem != null)
             {
-              activity = (EmacsActivity) getAttachedConsumer ();
+              activity = (EmacsActivity) tem;
               activity.syncFullscreenWith (EmacsWindow.this);
             }
         }