commit 2243aa6dd9af7ce7a0881c695cc305bf87c83064
author Prabhanjan Kandula <pkandula@codeaurora.org> Thu Oct 24 12:58:55 2013 +0530
committer Prabhanjan Kandula <pkandula@codeaurora.org> Tue Oct 29 01:00:20 2013 +0530
tree f4f3f8a4e84d1cf1aad40fa53b9fdca51db74fda
parent 67b7322ea3ddd5a5da84501f87c141d79e2680d0

hwcomposer : Fix cache redraw logic of MDP composition.

Redraw the cache if current frame cache/drop  data doesn't
match with cached frame data. Frame buffer z-order, fbcount
and mdp count are not reliable. With same fbz, fbcount and
mdpcount it is possible that layers in previous cached
frame are not part of current frame fb cache.

Change-Id: I858228dc1a3a8ab8673ab8d294e54fdbf43cc1ad

libhwcomposer/hwc_mdpcomp.cpp

diff --git a/libhwcomposer/hwc_mdpcomp.cpp b/libhwcomposer/hwc_mdpcomp.cpp
index ff33e94..aacad00 100644
--- a/libhwcomposer/hwc_mdpcomp.cpp
+++ b/libhwcomposer/hwc_mdpcomp.cpp
@@ -242,10 +242,9 @@
 
 void MDPComp::LayerCache::reset() {
     memset(&hnd, 0, sizeof(hnd));
-    mdpCount = 0;
-    fbCount = 0;
+    memset(&isFBComposed, true, sizeof(isFBComposed));
+    memset(&drop, false, sizeof(drop));
     layerCount = 0;
-    fbZ = -1;
 }
 
 void MDPComp::LayerCache::cacheAll(hwc_display_contents_1_t* list) {
@@ -256,10 +255,21 @@
 }
 
 void MDPComp::LayerCache::updateCounts(const FrameInfo& curFrame) {
-    mdpCount = curFrame.mdpCount;
-    fbCount = curFrame.fbCount;
     layerCount = curFrame.layerCount;
-    fbZ = curFrame.fbZ;
+    memcpy(&isFBComposed, &curFrame.isFBComposed, sizeof(isFBComposed));
+    memcpy(&drop, &curFrame.drop, sizeof(drop));
+}
+
+bool MDPComp::LayerCache::isSameFrame(const FrameInfo& curFrame) {
+    if(layerCount != curFrame.layerCount)
+        return false;
+    for(int i = 0; i < curFrame.layerCount; i++) {
+        if((curFrame.isFBComposed[i] != isFBComposed[i]) ||
+                (curFrame.drop[i] != drop[i])) {
+            return false;
+        }
+    }
+    return true;
 }
 
 bool MDPComp::isSupportedForMDPComp(hwc_context_t *ctx, hwc_layer_1_t* layer) {
@@ -1084,13 +1094,9 @@
         } else { //Success
             //Any change in composition types needs an FB refresh
             mCurrentFrame.needsRedraw = false;
-            if(mCurrentFrame.fbCount &&
-                    ((mCurrentFrame.mdpCount != mCachedFrame.mdpCount) ||
-                     (mCurrentFrame.fbCount != mCachedFrame.fbCount) ||
-                     (mCurrentFrame.fbZ != mCachedFrame.fbZ) ||
-                     (!mCurrentFrame.mdpCount) ||
+            if(!mCachedFrame.isSameFrame(mCurrentFrame) ||
                      (list->flags & HWC_GEOMETRY_CHANGED) ||
-                     isSkipPresent(ctx, mDpy))) {
+                     isSkipPresent(ctx, mDpy)) {
                 mCurrentFrame.needsRedraw = true;
             }
         }