diff --git a/graphics/composer/2.1/utils/hwc2on1adapter/HWC2On1Adapter.cpp b/graphics/composer/2.1/utils/hwc2on1adapter/HWC2On1Adapter.cpp
index 366d641..3d138f7 100644
--- a/graphics/composer/2.1/utils/hwc2on1adapter/HWC2On1Adapter.cpp
+++ b/graphics/composer/2.1/utils/hwc2on1adapter/HWC2On1Adapter.cpp
@@ -1921,8 +1921,8 @@
     mHwc1Id(0),
     mHasUnsupportedPlaneAlpha(false) {}
 
-bool HWC2On1Adapter::SortLayersByZ::operator()(
-        const std::shared_ptr<Layer>& lhs, const std::shared_ptr<Layer>& rhs) {
+bool HWC2On1Adapter::SortLayersByZ::operator()(const std::shared_ptr<Layer>& lhs,
+                                               const std::shared_ptr<Layer>& rhs) const {
     return lhs->getZ() < rhs->getZ();
 }
 
diff --git a/graphics/composer/2.1/utils/hwc2on1adapter/include/hwc2on1adapter/HWC2On1Adapter.h b/graphics/composer/2.1/utils/hwc2on1adapter/include/hwc2on1adapter/HWC2On1Adapter.h
index 3badfce..da771dc 100644
--- a/graphics/composer/2.1/utils/hwc2on1adapter/include/hwc2on1adapter/HWC2On1Adapter.h
+++ b/graphics/composer/2.1/utils/hwc2on1adapter/include/hwc2on1adapter/HWC2On1Adapter.h
@@ -130,8 +130,8 @@
 
     class SortLayersByZ {
         public:
-            bool operator()(const std::shared_ptr<Layer>& lhs,
-                    const std::shared_ptr<Layer>& rhs);
+         bool operator()(const std::shared_ptr<Layer>& lhs,
+                         const std::shared_ptr<Layer>& rhs) const;
     };
 
     // The semantics of the fences returned by the device differ between