Reduce display device log spam.

Don't repeat all of the display properties every time the display
just switches states.

Bug: 19996401
Change-Id: I9a1bd56f6e079b1c3f94e4be6ee2745a6df38d21

3 files changed, 65 insertions, 29 deletions

diff --git a/services/core/java/com/android/server/display/DisplayDevice.java b/services/core/java/com/android/server/display/DisplayDevice.java
index e16be71..ee36972 100644
--- a/services/core/java/com/android/server/display/DisplayDevice.java
+++ b/services/core/java/com/android/server/display/DisplayDevice.java
@@ -47,6 +47,10 @@ abstract class DisplayDevice {
     // within a transaction from performTraversalInTransactionLocked.
     private Surface mCurrentSurface;
 
+    // DEBUG STATE: Last device info which was written to the log, or null if none.
+    // Do not use for any other purpose.
+    DisplayDeviceInfo mDebugLastLoggedDeviceInfo;
+
     public DisplayDevice(DisplayAdapter displayAdapter, IBinder displayToken, String uniqueId) {
         mDisplayAdapter = displayAdapter;
         mDisplayToken = displayToken;
diff --git a/services/core/java/com/android/server/display/DisplayDeviceInfo.java b/services/core/java/com/android/server/display/DisplayDeviceInfo.java
index d1e73f0..ebf6e4e 100644
--- a/services/core/java/com/android/server/display/DisplayDeviceInfo.java
+++ b/services/core/java/com/android/server/display/DisplayDeviceInfo.java
@@ -104,6 +104,16 @@ final class DisplayDeviceInfo {
     public static final int TOUCH_EXTERNAL = 2;
 
     /**
+     * Diff result: The {@link #state} fields differ.
+     */
+    public static final int DIFF_STATE = 1 << 0;
+
+    /**
+     * Diff result: Other fields differ.
+     */
+    public static final int DIFF_OTHER = 1 << 1;
+
+    /**
      * Gets the name of the display device, which may be derived from EDID or
      * other sources. The name may be localized and displayed to the user.
      */
@@ -238,26 +248,39 @@ final class DisplayDeviceInfo {
     }
 
     public boolean equals(DisplayDeviceInfo other) {
-        return other != null
-                && Objects.equal(name, other.name)
-                && Objects.equal(uniqueId, other.uniqueId)
-                && width == other.width
-                && height == other.height
-                && refreshRate == other.refreshRate
-                && Arrays.equals(supportedRefreshRates, other.supportedRefreshRates)
-                && densityDpi == other.densityDpi
-                && xDpi == other.xDpi
-                && yDpi == other.yDpi
-                && appVsyncOffsetNanos == other.appVsyncOffsetNanos
-                && presentationDeadlineNanos == other.presentationDeadlineNanos
-                && flags == other.flags
-                && touch == other.touch
-                && rotation == other.rotation
-                && type == other.type
-                && Objects.equal(address, other.address)
-                && state == other.state
-                && ownerUid == other.ownerUid
-                && Objects.equal(ownerPackageName, other.ownerPackageName);
+        return other != null && diff(other) == 0;
+    }
+
+    /**
+     * Computes the difference between display device infos.
+     * Assumes other is not null.
+     */
+    public int diff(DisplayDeviceInfo other) {
+        int diff = 0;
+        if (state != other.state) {
+            diff |= DIFF_STATE;
+        }
+        if (!Objects.equal(name, other.name)
+                || !Objects.equal(uniqueId, other.uniqueId)
+                || width != other.width
+                || height != other.height
+                || refreshRate != other.refreshRate
+                || !Arrays.equals(supportedRefreshRates, other.supportedRefreshRates)
+                || densityDpi != other.densityDpi
+                || xDpi != other.xDpi
+                || yDpi != other.yDpi
+                || appVsyncOffsetNanos != other.appVsyncOffsetNanos
+                || presentationDeadlineNanos != other.presentationDeadlineNanos
+                || flags != other.flags
+                || touch != other.touch
+                || rotation != other.rotation
+                || type != other.type
+                || !Objects.equal(address, other.address)
+                || ownerUid != other.ownerUid
+                || !Objects.equal(ownerPackageName, other.ownerPackageName)) {
+            diff |= DIFF_OTHER;
+        }
+        return diff;
     }
 
     @Override
diff --git a/services/core/java/com/android/server/display/DisplayManagerService.java b/services/core/java/com/android/server/display/DisplayManagerService.java
index 9ea0444..1e87433 100644
--- a/services/core/java/com/android/server/display/DisplayManagerService.java
+++ b/services/core/java/com/android/server/display/DisplayManagerService.java
@@ -668,13 +668,14 @@ public final class DisplayManagerService extends SystemService {
     }
 
     private void handleDisplayDeviceAddedLocked(DisplayDevice device) {
+        DisplayDeviceInfo info = device.getDisplayDeviceInfoLocked();
         if (mDisplayDevices.contains(device)) {
-            Slog.w(TAG, "Attempted to add already added display device: "
-                    + device.getDisplayDeviceInfoLocked());
+            Slog.w(TAG, "Attempted to add already added display device: " + info);
             return;
         }
 
-        Slog.i(TAG, "Display device added: " + device.getDisplayDeviceInfoLocked());
+        Slog.i(TAG, "Display device added: " + info);
+        device.mDebugLastLoggedDeviceInfo = info;
 
         mDisplayDevices.add(device);
         addLogicalDisplayLocked(device);
@@ -687,13 +688,20 @@ public final class DisplayManagerService extends SystemService {
 
     private void handleDisplayDeviceChanged(DisplayDevice device) {
         synchronized (mSyncRoot) {
+            DisplayDeviceInfo info = device.getDisplayDeviceInfoLocked();
             if (!mDisplayDevices.contains(device)) {
-                Slog.w(TAG, "Attempted to change non-existent display device: "
-                        + device.getDisplayDeviceInfoLocked());
+                Slog.w(TAG, "Attempted to change non-existent display device: " + info);
                 return;
             }
 
-            Slog.i(TAG, "Display device changed: " + device.getDisplayDeviceInfoLocked());
+            int diff = device.mDebugLastLoggedDeviceInfo.diff(info);
+            if (diff == DisplayDeviceInfo.DIFF_STATE) {
+                Slog.i(TAG, "Display device changed state: \"" + info.name
+                        + "\", " + Display.stateToString(info.state));
+            } else if (diff != 0) {
+                Slog.i(TAG, "Display device changed: " + info);
+            }
+            device.mDebugLastLoggedDeviceInfo = info;
 
             device.applyPendingDisplayDeviceInfoChangesLocked();
             if (updateLogicalDisplaysLocked()) {
@@ -708,13 +716,14 @@ public final class DisplayManagerService extends SystemService {
         }
     }
     private void handleDisplayDeviceRemovedLocked(DisplayDevice device) {
+        DisplayDeviceInfo info = device.getDisplayDeviceInfoLocked();
         if (!mDisplayDevices.remove(device)) {
-            Slog.w(TAG, "Attempted to remove non-existent display device: "
-                    + device.getDisplayDeviceInfoLocked());
+            Slog.w(TAG, "Attempted to remove non-existent display device: " + info);
             return;
         }
 
-        Slog.i(TAG, "Display device removed: " + device.getDisplayDeviceInfoLocked());
+        Slog.i(TAG, "Display device removed: " + info);
+        device.mDebugLastLoggedDeviceInfo = info;
 
         updateLogicalDisplaysLocked();
         scheduleTraversalLocked(false);