[sf] only update the last latch time if the layer has a buffer
If we apply a transaction that does not latch a buffer, we
incorrectly updated the last latch time. In the next vsync,
if we presented a buffer late, we would misclassify the
jank as buffer stuffing.
Fix this by only updating the latch time if the layer has
a buffer.
Test: verify in perfetto traces
Fixes: 270041584
Change-Id: I423a28803a2660ada80ef554469f3977c389fbfa
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 433606a..ded607e 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -3037,6 +3037,10 @@
mLastClientCompositionFence);
mLastClientCompositionFence = nullptr;
}
+ } else {
+ // if we are latching a buffer for the first time then clear the mLastLatchTime since
+ // we don't want to incorrectly classify a frame if we miss the desired present time.
+ updateLastLatchTime(0);
}
mDrawingState.producerId = bufferData.producerId;