diff --git a/xen/drivers/char/serial.c b/xen/drivers/char/serial.c
index bbbe758788..e3c3564089 100644
--- a/xen/drivers/char/serial.c
+++ b/xen/drivers/char/serial.c
@@ -15,9 +15,6 @@
 
 #include <asm/processor.h>
 
-/* Never drop characters, even if the async transmit buffer fills. */
-/* #define SERIAL_NEVER_DROP_CHARS 1 */
-
 unsigned int __ro_after_init serial_txbufsz = CONFIG_SERIAL_TX_BUFSIZE;
 size_param("serial_tx_buffer", serial_txbufsz);