--- zzzz-none-000/linux-3.10.107/include/linux/tty_flip.h	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/include/linux/tty_flip.h	2021-02-04 17:41:59.000000000 +0000
@@ -1,6 +1,8 @@
 #ifndef _LINUX_TTY_FLIP_H
 #define _LINUX_TTY_FLIP_H
 
+extern int tty_buffer_set_limit(struct tty_port *port, int limit);
+extern int tty_buffer_space_avail(struct tty_port *port);
 extern int tty_buffer_request_room(struct tty_port *port, size_t size);
 extern int tty_insert_flip_string_flags(struct tty_port *port,
 		const unsigned char *chars, const char *flags, size_t size);
@@ -8,8 +10,6 @@
 		const unsigned char *chars, char flag, size_t size);
 extern int tty_prepare_flip_string(struct tty_port *port,
 		unsigned char **chars, size_t size);
-extern int tty_prepare_flip_string_flags(struct tty_port *port,
-		unsigned char **chars, char **flags, size_t size);
 extern void tty_flip_buffer_push(struct tty_port *port);
 void tty_schedule_flip(struct tty_port *port);
 
@@ -17,9 +17,13 @@
 					unsigned char ch, char flag)
 {
 	struct tty_buffer *tb = port->buf.tail;
-	if (tb && tb->used < tb->size) {
-		tb->flag_buf_ptr[tb->used] = flag;
-		tb->char_buf_ptr[tb->used++] = ch;
+	int change;
+
+	change = (tb->flags & TTYB_NORMAL) && (flag != TTY_NORMAL);
+	if (!change && tb->used < tb->size) {
+		if (~tb->flags & TTYB_NORMAL)
+			*flag_buf_ptr(tb, tb->used) = flag;
+		*char_buf_ptr(tb, tb->used++) = ch;
 		return 1;
 	}
 	return tty_insert_flip_string_flags(port, &ch, &flag, 1);
@@ -31,4 +35,7 @@
 	return tty_insert_flip_string_fixed_flag(port, chars, TTY_NORMAL, size);
 }
 
+extern void tty_buffer_lock_exclusive(struct tty_port *port);
+extern void tty_buffer_unlock_exclusive(struct tty_port *port);
+
 #endif /* _LINUX_TTY_FLIP_H */