diff --git a/src/connection.c b/src/connection.c
index fa01545..05fa8f8 100644
--- a/src/connection.c
+++ b/src/connection.c
@@ -123,7 +123,10 @@ static void
 wl_buffer_get_iov(struct wl_buffer *b, struct iovec *iov, int *count)
 {
 	int head, tail;
-
+	if (b->head == b->tail) {
+		*count = 0;
+		return;
+	}
 	head = MASK(b->head);
 	tail = MASK(b->tail);
 	if (tail < head) {
@@ -275,14 +278,12 @@ wl_connection_data(struct wl_connection *connection, uint32_t mask)
 		do {
 			len = sendmsg(connection->fd, &msg,
 				      MSG_NOSIGNAL | MSG_DONTWAIT);
-		} while (len < 0 && errno == EINTR);
+		} while (len < 0 && (errno == EINTR || errno == EAGAIN));
 
-		if (len == -1 && errno == EPIPE) {
-			return -1;
-		} else if (len < 0) {
+		if (len < 0) {
 			fprintf(stderr,
-				"write error for connection %p, fd %d: %m\n",
-				connection, connection->fd);
+				"write error for connection %p, fd %d: %m (%d)\n",
+				connection, connection->fd, errno);
 			return -1;
 		}
 
@@ -311,7 +312,7 @@ wl_connection_data(struct wl_connection *connection, uint32_t mask)
 
 		do {
 			len = recvmsg(connection->fd, &msg, MSG_CMSG_CLOEXEC);
-		} while (len < 0 && errno == EINTR);
+		} while (len < 0 && (errno == EINTR || errno == EAGAIN));
 
 		if (len < 0) {
 			fprintf(stderr,
@@ -554,8 +555,8 @@ wl_connection_vmarshal(struct wl_connection *connection,
 	return closure;
 
 err:
-	printf("request too big to marshal, maximum size is %lu\n",
-	       sizeof closure->buffer);
+	printf("request too big to marshal, maximum size is %u\n",
+	       (unsigned)(sizeof closure->buffer));
 	errno = ENOMEM;
 	return NULL;
 }
@@ -584,8 +585,8 @@ wl_connection_demarshal(struct wl_connection *connection,
 
 	extra_space = wl_message_size_extra(message);
 	if (sizeof closure->buffer < size + extra_space) {
-		printf("request too big to demarshal, maximum %lu actual %d\n",
-		       sizeof closure->buffer, size + extra_space);
+		printf("request too big to demarshal, maximum %u actual %d\n",
+		       (unsigned)(sizeof closure->buffer), size + extra_space);
 		errno = ENOMEM;
 		wl_connection_consume(connection, size);
 		return NULL;
diff --git a/src/wayland-server.c b/src/wayland-server.c
index 899c094..075ebe8 100644
--- a/src/wayland-server.c
+++ b/src/wayland-server.c
@@ -161,6 +161,9 @@ wl_resource_post_error(struct wl_resource *resource,
 	vsnprintf(buffer, sizeof buffer, msg, ap);
 	va_end(ap);
 
+	if (wl_debug)
+		fprintf(stderr, "%s\n", buffer);
+
 	client->error = 1;
 
 	/*
@@ -212,7 +215,8 @@ wl_client_connection_data(int fd, uint32_t mask, void *data)
 		if (resource == NULL) {
 			wl_resource_post_error(client->display_resource,
 					       WL_DISPLAY_ERROR_INVALID_OBJECT,
-					       "invalid object %d", p[0]);
+					       "invalid object %d (method %d, size %d)",
+					       p[0], opcode, size);
 			break;
 		}
 
@@ -220,9 +224,10 @@ wl_client_connection_data(int fd, uint32_t mask, void *data)
 		if (opcode >= object->interface->method_count) {
 			wl_resource_post_error(client->display_resource,
 					       WL_DISPLAY_ERROR_INVALID_METHOD,
-					       "invalid method %d, object %s@%d",
+					       "invalid method %d (size %d), object %s@%d",
+					       opcode, size,
 					       object->interface->name,
-					       object->id, opcode);
+					       object->id);
 			break;
 		}