Flush less frequently in QueryGL.

src/libANGLE/renderer/gl/QueryGL.cpp

@@ -44,6 +44,9 @@ GLuint64 MergeQueryResults(gl::QueryType type, GLuint64 currentResult, GLuint64
     }
 }
 
+// Some drivers tend to hang when flushing pending queries.  Wait until this number of queries have
+// added up before checking if results are ready.
+constexpr uint32_t kPauseResumeFlushThreshold = 5;
 }  // anonymous namespace
 
 namespace rx
@@ -159,7 +162,12 @@ angle::Result StandardQueryGL::pause(const gl::Context *context)
     }
 
     // Flush to make sure the pending queries don't add up too much.
-    return flush(context, false);
+    if (mPendingQueries.size() >= kPauseResumeFlushThreshold)
+    {
+        ANGLE_TRY(flush(context, false));
+    }
+
+    return angle::Result::Continue;
 }
 
 angle::Result StandardQueryGL::resume(const gl::Context *context)
@@ -167,7 +175,11 @@ angle::Result StandardQueryGL::resume(const gl::Context *context)
     if (mActiveQuery == 0)
     {
         // Flush to make sure the pending queries don't add up too much.
-        ANGLE_TRY(flush(context, false));
+        if (mPendingQueries.size() >= kPauseResumeFlushThreshold)
+        {
+            ANGLE_TRY(flush(context, false));
+        }
+
         mFunctions->genQueries(1, &mActiveQuery);
         mStateManager->beginQuery(mType, this, mActiveQuery);
     }