Merge "DO NOT MERGE: SurfaceFlinger: Don't wake for pending transactions." into rvc-dev

3 files changed, 16 insertions, 3 deletions

diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 5a4d9cd6b9..96552770c4 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -855,11 +855,14 @@ bool Layer::applyPendingStates(State* stateToCommit) {
         }
     }
 
-    // If we still have pending updates, wake SurfaceFlinger back up and point
-    // it at this layer so we can process them
+    // If we still have pending updates, we need to ensure SurfaceFlinger
+    // will keep calling doTransaction, and so we set the transaction flags.
+    // However, our pending states won't clear until a frame is available,
+    // and so there is no need to specifically trigger a wakeup. Rather
+    // we set the flags and wait for something else to wake us up.
     if (!mPendingStates.empty()) {
         setTransactionFlags(eTransactionNeeded);
-        mFlinger->setTransactionFlags(eTraversalNeeded);
+        mFlinger->setTransactionFlagsNoWake(eTraversalNeeded);
     }
 
     mCurrentState.modified = false;
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 83f49dd46b..2e2273594e 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -3243,6 +3243,10 @@ uint32_t SurfaceFlinger::setTransactionFlags(uint32_t flags,
     return old;
 }
 
+uint32_t SurfaceFlinger::setTransactionFlagsNoWake(uint32_t flags) {
+    return mTransactionFlags.fetch_or(flags);
+}
+
 bool SurfaceFlinger::flushTransactionQueues() {
     // to prevent onHandleDestroyed from being called while the lock is held,
     // we must keep a copy of the transactions (specifically the composer
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index 4cfbdddc31..113b03557f 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -628,6 +628,12 @@ private:
     uint32_t peekTransactionFlags();
     // Can only be called from the main thread or with mStateLock held
     uint32_t setTransactionFlags(uint32_t flags);
+    // Set the transaction flags, but don't trigger a wakeup! We use this cases where
+    // there are still pending transactions but we know they won't be ready until a frame
+    // arrives from a different layer. So we need to ensure we performTransaction from invalidate
+    // but there is no need to try and wake up immediately to do it. Rather we rely on
+    // onFrameAvailable to wake us up.
+    uint32_t setTransactionFlagsNoWake(uint32_t flags);
     uint32_t setTransactionFlags(uint32_t flags, Scheduler::TransactionStart transactionStart);
     void commitTransaction() REQUIRES(mStateLock);
     void commitOffscreenLayers();