Fix sync issue with handling display state changes
We may miss some state changes if a display state change comes between
processDisplayChangesLocked and commitTransactions. Fix this by grabbing
the state lock for the duration of display updates in commit.
Test: steps in bug
Bug: 330105711, 330103914, 328539539
Change-Id: I4798961551f78d75c45ead6dea5ebca895e5ef7d
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index bf210af..7d3e2c8 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -2254,7 +2254,7 @@
outTransactionsAreEmpty = !needsTraversal;
const bool shouldCommit = (getTransactionFlags() & ~eTransactionFlushNeeded) || needsTraversal;
if (shouldCommit) {
- commitTransactions();
+ commitTransactionsLegacy();
}
bool mustComposite = latchBuffers() || shouldCommit;
@@ -2378,8 +2378,14 @@
mLayerHierarchyBuilder.update(mLayerLifecycleManager);
}
+ // Keep a copy of the drawing state (that is going to be overwritten
+ // by commitTransactionsLocked) outside of mStateLock so that the side
+ // effects of the State assignment don't happen with mStateLock held,
+ // which can cause deadlocks.
+ State drawingState(mDrawingState);
+ Mutex::Autolock lock(mStateLock);
bool mustComposite = false;
- mustComposite |= applyAndCommitDisplayTransactionStates(update.transactions);
+ mustComposite |= applyAndCommitDisplayTransactionStatesLocked(update.transactions);
{
ATRACE_NAME("LayerSnapshotBuilder:update");
@@ -2418,7 +2424,7 @@
bool newDataLatched = false;
if (!mLegacyFrontEndEnabled) {
ATRACE_NAME("DisplayCallbackAndStatsUpdates");
- mustComposite |= applyTransactions(update.transactions, vsyncId);
+ mustComposite |= applyTransactionsLocked(update.transactions, vsyncId);
traverseLegacyLayers([&](Layer* layer) { layer->commitTransaction(); });
const nsecs_t latchTime = systemTime();
bool unused = false;
@@ -3259,6 +3265,19 @@
void SurfaceFlinger::commitTransactions() {
ATRACE_CALL();
+ mDebugInTransaction = systemTime();
+
+ // Here we're guaranteed that some transaction flags are set
+ // so we can call commitTransactionsLocked unconditionally.
+ // We clear the flags with mStateLock held to guarantee that
+ // mCurrentState won't change until the transaction is committed.
+ mScheduler->modulateVsync({}, &VsyncModulator::onTransactionCommit);
+ commitTransactionsLocked(clearTransactionFlags(eTransactionMask));
+ mDebugInTransaction = 0;
+}
+
+void SurfaceFlinger::commitTransactionsLegacy() {
+ ATRACE_CALL();
// Keep a copy of the drawing state (that is going to be overwritten
// by commitTransactionsLocked) outside of mStateLock so that the side
@@ -5228,9 +5247,8 @@
return needsTraversal;
}
-bool SurfaceFlinger::applyAndCommitDisplayTransactionStates(
+bool SurfaceFlinger::applyAndCommitDisplayTransactionStatesLocked(
std::vector<TransactionState>& transactions) {
- Mutex::Autolock lock(mStateLock);
bool needsTraversal = false;
uint32_t transactionFlags = 0;
for (auto& transaction : transactions) {
@@ -6018,7 +6036,8 @@
if (mLegacyFrontEndEnabled) {
applyTransactions(transactions, VsyncId{0});
} else {
- applyAndCommitDisplayTransactionStates(transactions);
+ Mutex::Autolock lock(mStateLock);
+ applyAndCommitDisplayTransactionStatesLocked(transactions);
}
{