diff --git a/graphics/allocator/aidl/android/hardware/graphics/allocator/IAllocator.aidl b/graphics/allocator/aidl/android/hardware/graphics/allocator/IAllocator.aidl
index 8c3ca96..92dfd4f 100644
--- a/graphics/allocator/aidl/android/hardware/graphics/allocator/IAllocator.aidl
+++ b/graphics/allocator/aidl/android/hardware/graphics/allocator/IAllocator.aidl
@@ -29,8 +29,8 @@
      * @param descriptor Properties of the buffers to allocate. This must be
      *     obtained from IMapper::createDescriptor().
      * @param count The number of buffers to allocate.
-     * @return An AllocationResult containing the result of an error, or
-     *         an AllocationError status
+     * @return An AllocationResult containing the result of the allocation
+     * @throws AllocationError on failure
      */
     AllocationResult allocate(in byte[] descriptor, in int count);
 }
diff --git a/graphics/common/aidl/android/hardware/graphics/common/BufferUsage.aidl b/graphics/common/aidl/android/hardware/graphics/common/BufferUsage.aidl
index 60dfbfb..17f4684 100644
--- a/graphics/common/aidl/android/hardware/graphics/common/BufferUsage.aidl
+++ b/graphics/common/aidl/android/hardware/graphics/common/BufferUsage.aidl
@@ -125,6 +125,14 @@
     * presents from SF (such as for panel self-refresh), but for any given
     * present the buffer must be composited from even if it otherwise appears
     * to be the same as a previous composition.
+    *
+    * If the GPU & HWC supports EGL_SINGLE_BUFFER, then it is recommended that
+    * FRONT_BUFFER usage is supported for the same formats as supported by
+    * EGL_SINGLE_BUFFER. In particular, it is recommended that the following
+    * combination is supported when possible:
+    *    Format = RGBA_8888
+    *    Usage = FRONT_BUFFER | GPU_RENDER_TARGET | COMPOSER_OVERLAY
+    *
     */
     FRONT_BUFFER                       = 1L << 32,