--- zzzz-none-000/linux-4.1.52/drivers/tty/n_tty.c	2018-05-28 02:26:45.000000000 +0000
+++ bcm63-7530ax-731/linux-4.1.52/drivers/tty/n_tty.c	2022-03-02 11:37:13.000000000 +0000
@@ -2375,6 +2375,15 @@
 
 	down_read(&tty->termios_rwsem);
 
+#if defined(CONFIG_AVM_ENHANCED)
+	if (tty->driver->ops->avm_console_enabled) {
+		if (!tty->driver->ops->avm_console_enabled(tty)) {
+			b += nr;
+			goto skip_out;
+		}
+	}
+#endif
+
 	/* Write out any echoed characters that are still pending */
 	process_echoes(tty);
 
@@ -2439,6 +2448,9 @@
 	}
 break_out:
 	remove_wait_queue(&tty->write_wait, &wait);
+#if defined(CONFIG_AVM_ENHANCED)
+skip_out:
+#endif
 	if (b - buf != nr && tty->fasync)
 		set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 	up_read(&tty->termios_rwsem);