--- a/widget/gonk/HwcComposer2D.cpp
+++ b/widget/gonk/HwcComposer2D.cpp
@@ -152,21 +152,23 @@ HwcComposer2D::PrepareLayerList(Layer* a
 
     bool fillColor = false;
 
     const nsIntRegion& visibleRegion = aLayer->GetEffectiveVisibleRegion();
     if (visibleRegion.IsEmpty()) {
         return true;
     }
 
-    float opacity = aLayer->GetEffectiveOpacity();
-    if (opacity < 1) {
+    uint8_t opacity = std::min(0xFF, (int)(aLayer->GetEffectiveOpacity() * 256.0));
+#if ANDROID_VERSION < 18
+    if (opacity < 0xFF) {
         LOGD("%s Layer has planar semitransparency which is unsupported", aLayer->Name());
         return false;
     }
+#endif
 
     nsIntRect clip;
     if (!HwcUtils::CalculateClipRect(aParentTransform * aGLWorldTransform,
                                      aLayer->GetEffectiveClipRect(),
                                      aClip,
                                      &clip))
     {
         LOGD("%s Clip rect is empty. Skip layer", aLayer->Name());
@@ -271,17 +273,17 @@ HwcComposer2D::PrepareLayerList(Layer* a
     hwcLayer.flags = 0;
     hwcLayer.hints = 0;
     hwcLayer.blending = HWC_BLENDING_PREMULT;
 #if ANDROID_VERSION >= 18
     hwcLayer.compositionType = HWC_FRAMEBUFFER;
 
     hwcLayer.acquireFenceFd = -1;
     hwcLayer.releaseFenceFd = -1;
-    hwcLayer.planeAlpha = 0xFF; // Until plane alpha is enabled
+    hwcLayer.planeAlpha = opacity;
 #else
     hwcLayer.compositionType = HwcUtils::HWC_USE_COPYBIT;
 #endif
 
     if (!fillColor) {
         if (state.FormatRBSwapped()) {
             if (!mRBSwapSupport) {
                 LOGD("No R/B swap support in H/W Composer");