Index: uspace/drv/char/ns8250/ns8250.c
===================================================================
--- uspace/drv/char/ns8250/ns8250.c	(revision 8486c070d3e8193fcd8774597aa3c3438d3ba2c9)
+++ uspace/drv/char/ns8250/ns8250.c	(revision 91ecaa1074636a3d3b17808616e1c5a4979a1928)
@@ -179,4 +179,6 @@
 	/** The fibril mutex for synchronizing the access to the device. */
 	fibril_mutex_t mutex;
+	/** Indicates that some data has become available */
+	fibril_condvar_t input_buffer_available;
 	/** True if device is removed. */
 	bool removed;
@@ -238,7 +240,11 @@
 {
 	ns8250_t *ns = NS8250(fun);
-	int ret = EOK;
+	int ret = 0;
+	
+	if (count == 0) return 0;
 	
 	fibril_mutex_lock(&ns->mutex);
+	while (buf_is_empty(&ns->input_buffer))
+		fibril_condvar_wait(&ns->input_buffer_available, &ns->mutex);
 	while (!buf_is_empty(&ns->input_buffer) && (size_t)ret < count) {
 		buf[ret] = (char)buf_pop_front(&ns->input_buffer);
@@ -739,4 +745,5 @@
 			
 			if (ns->client_connected) {
+				bool buf_was_empty = buf_is_empty(&ns->input_buffer);
 				if (!buf_push_back(&ns->input_buffer, val)) {
 					ddf_msg(LVL_WARN, "Buffer overflow on "
@@ -746,4 +753,6 @@
 					    "to the buffer of %s.",
 					    val, ns->dev->name);
+					if (buf_was_empty)
+						fibril_condvar_broadcast(&ns->input_buffer_available);
 				}
 			}
@@ -811,4 +820,5 @@
 	
 	fibril_mutex_initialize(&ns->mutex);
+	fibril_condvar_initialize(&ns->input_buffer_available);
 	ns->dev = dev;