diff --git a/contrib/debug/flags.c b/contrib/debug/flags.c
index cf11a71..2638dd3 100644
--- a/contrib/debug/flags.c
+++ b/contrib/debug/flags.c
@@ -122,7 +122,6 @@
 	SHOW_FLAG(f, CO_FL_ADDR_TO_SET);
 	SHOW_FLAG(f, CO_FL_ADDR_FROM_SET);
 	SHOW_FLAG(f, CO_FL_WAIT_ROOM);
-	SHOW_FLAG(f, CO_FL_WAIT_DATA);
 	SHOW_FLAG(f, CO_FL_XPRT_READY);
 	SHOW_FLAG(f, CO_FL_CTRL_READY);
 	SHOW_FLAG(f, CO_FL_CURR_WR_ENA);
diff --git a/include/proto/connection.h b/include/proto/connection.h
index 2380bb8..e867446 100644
--- a/include/proto/connection.h
+++ b/include/proto/connection.h
@@ -178,7 +178,7 @@
  */
 static inline void conn_refresh_polling_flags(struct connection *conn)
 {
-	conn->flags &= ~(CO_FL_WAIT_ROOM | CO_FL_WAIT_DATA);
+	conn->flags &= ~CO_FL_WAIT_ROOM;
 
 	if (conn_ctrl_ready(conn)) {
 		unsigned int flags = conn->flags & ~(CO_FL_CURR_RD_ENA | CO_FL_CURR_WR_ENA);
diff --git a/include/types/connection.h b/include/types/connection.h
index 9d1b51a..60d9772 100644
--- a/include/types/connection.h
+++ b/include/types/connection.h
@@ -74,12 +74,12 @@
 	CO_FL_CTRL_READY    = 0x00000100, /* FD was registered, fd_delete() needed */
 	CO_FL_XPRT_READY    = 0x00000200, /* xprt_init() done, xprt_close() needed */
 
-	/* These flags are used by data layers to indicate they had to stop
-	 * sending data because a buffer was empty (WAIT_DATA) or stop receiving
-	 * data because a buffer was full (WAIT_ROOM). The connection handler
-	 * clears them before first calling the I/O and data callbacks.
+	/* unused : 0x00000400 */
+
+	/* This flag is used by data layers to indicate they had to stop
+	 * receiving data because a buffer was full. The connection handler
+	 * clears it before first calling the I/O and data callbacks.
 	 */
-	CO_FL_WAIT_DATA     = 0x00000400,  /* data source is empty */
 	CO_FL_WAIT_ROOM     = 0x00000800,  /* data sink is full */
 
 	/* These flags are used to report whether the from/to addresses are set or not */
diff --git a/src/connection.c b/src/connection.c
index c23f464..f054cd1 100644
--- a/src/connection.c
+++ b/src/connection.c
@@ -109,7 +109,7 @@
 	}
 
 	if (conn->xprt && fd_send_ready(fd) &&
-	    ((conn->flags & (CO_FL_DATA_WR_ENA|CO_FL_WAIT_DATA|CO_FL_ERROR|CO_FL_HANDSHAKE)) == CO_FL_DATA_WR_ENA)) {
+	    ((conn->flags & (CO_FL_DATA_WR_ENA|CO_FL_ERROR|CO_FL_HANDSHAKE)) == CO_FL_DATA_WR_ENA)) {
 		/* force reporting of activity by clearing the previous flags :
 		 * we'll have at least ERROR or CONNECTED at the end of an I/O,
 		 * both of which will be detected below.
diff --git a/src/stream_interface.c b/src/stream_interface.c
index 4a00388..47ba8c1 100644
--- a/src/stream_interface.c
+++ b/src/stream_interface.c
@@ -633,7 +633,7 @@
 	/* when we're here, we already know that there is no spliced
 	 * data left, and that there are sendable buffered data.
 	 */
-	if (!(conn->flags & (CO_FL_ERROR | CO_FL_SOCK_WR_SH | CO_FL_DATA_WR_SH | CO_FL_WAIT_DATA | CO_FL_HANDSHAKE))) {
+	if (!(conn->flags & (CO_FL_ERROR | CO_FL_SOCK_WR_SH | CO_FL_DATA_WR_SH | CO_FL_HANDSHAKE))) {
 		/* check if we want to inform the kernel that we're interested in
 		 * sending more data after this call. We want this if :
 		 *  - we're about to close after this last send and want to merge