Discard invisible surfaces

* Jiwen found that we would try to post invisible layers, and this
  would cause a hang.
* Check to see if the surface is invisible, and if so, discard it

Test: Manually tested with particles
Change-Id: Id4a0813cb30bd48c3cfa4d13dcee59fcb5f58a8d

1 files changed, 9 insertions, 0 deletions

diff --git a/libs/vr/libvrflinger/display_surface.cpp b/libs/vr/libvrflinger/display_surface.cpp
index e1729f8cf0..7c821bfd68 100644
--- a/libs/vr/libvrflinger/display_surface.cpp
+++ b/libs/vr/libvrflinger/display_surface.cpp
@@ -381,6 +381,15 @@ void DisplaySurface::OnPostConsumer(
   ATRACE_NAME("DisplaySurface::OnPostConsumer");
   std::lock_guard<std::mutex> autolock(lock_);
 
+  if (!IsVisible()) {
+    ALOGD_IF(TRACE,
+             "DisplaySurface::OnPostConsumer: Discarding buffer_id=%d on "
+             "invisible surface.",
+             consumer->id());
+    consumer->Discard();
+    return;
+  }
+
   if (posted_buffers_.IsFull()) {
     ALOGE("Error: posted buffers full, overwriting");
     posted_buffers_.PopBack();