diff --git a/intern/cycles/kernel/geom/geom_volume.h b/intern/cycles/kernel/geom/geom_volume.h
index 7bd3933a1f8..ef02c01dec6 100644
--- a/intern/cycles/kernel/geom/geom_volume.h
+++ b/intern/cycles/kernel/geom/geom_volume.h
@@ -77,7 +77,6 @@ ccl_device float volume_attribute_float(KernelGlobals *kg, const ShaderData *sd,
 	if(dx) *dx = 0.0f;
 	if(dy) *dy = 0.0f;
 
-	/* todo: support float textures to lower memory usage for single floats */
 	return average(float4_to_float3(r));
 }
 
diff --git a/intern/cycles/render/image.cpp b/intern/cycles/render/image.cpp
index 102c6107fb7..40c48088c5a 100644
--- a/intern/cycles/render/image.cpp
+++ b/intern/cycles/render/image.cpp
@@ -196,6 +196,10 @@ ImageManager::ImageDataType ImageManager::get_image_metadata(const string& filen
 		return IMAGE_DATA_TYPE_BYTE4;
 }
 
+/* We use a consecutive slot counting scheme on the devices, in order
+ * float4, byte4, float.
+ * These functions convert the slot ids from ImageManager "images" ones
+ * to device ones and vice versa. */
 int ImageManager::type_index_to_flattened_slot(int slot, ImageDataType type)
 {
 	if(type == IMAGE_DATA_TYPE_BYTE4)