diff --git a/drivers/staging/greybus/greybus_protocols.h b/drivers/staging/greybus/greybus_protocols.h
index cd64ac84dad2388c105a1ec98030276f812a960e..6b192924a566adde43a993ac4f4dfc3a43fcc09f 100644
--- a/drivers/staging/greybus/greybus_protocols.h
+++ b/drivers/staging/greybus/greybus_protocols.h
@@ -1053,8 +1053,14 @@ struct gb_uart_serial_state_request {
 #define GB_LOOPBACK_TYPE_TRANSFER		0x03
 #define GB_LOOPBACK_TYPE_SINK			0x04
 
+/*
+ * Loopback request/response header format should be identical
+ * to simplify bandwidth and data movement analysis.
+ */
 struct gb_loopback_transfer_request {
 	__le32	len;
+	__le32  reserved0;
+	__le32  reserved1;
 	__u8	data[0];
 } __packed;