--- a/channels.c
+++ b/channels.c
@@ -1003,13 +1003,16 @@
     fd_set *readset, fd_set *writeset)
 {
+	u_int limit = c->remote_window;
+
 	/* check buffer limits */
 	if (!c->tcpwinsz || c->dynamic_window > 0)
 		c->tcpwinsz = channel_tcpwinsz();
 
-	c->remote_window = MIN(c->remote_window, 2 * c->tcpwinsz);
+	if (c->dynamic_window)
+		limit = MIN(limit, 2 * c->tcpwinsz);
 
 	if (c->istate == CHAN_INPUT_OPEN &&
-	    c->remote_window > 0 &&
-	    sshbuf_len(c->input) < c->remote_window &&
+	    limit > 0 &&
+	    sshbuf_len(c->input) < limit &&
 	    sshbuf_check_reserve(c->input, CHAN_RBUF) == 0)
 		FD_SET(c->rfd, readset);