DTLS depends on TIMING_C for now
diff --git a/include/polarssl/config.h b/include/polarssl/config.h
index abc2668..6e9050a 100644
--- a/include/polarssl/config.h
+++ b/include/polarssl/config.h
@@ -908,6 +908,11 @@
*
* Requires: POLARSSL_SSL_PROTO_TLS1_1
* or POLARSSL_SSL_PROTO_TLS1_2
+ * POLARSSL_TIMING_C
+ *
+ * \note Dependency on TIMING_C may be replaced by something more flexible
+ * (callbacks or abstraction layer in the next major version). Please contact
+ * us if you're having issues with this dependency.
*
* Comment this macro to disable support for DTLS
*/