diff --git a/hw/char/serial.c b/hw/char/serial.c
index 605b0d02f992cab219ca88d5de01daf30be0f980..6de6c297791a0e38347cd0ea15a80f4d72f79259 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -260,7 +260,7 @@ static void serial_xmit(SerialState *s)
         if (s->mcr & UART_MCR_LOOP) {
             /* in loopback mode, say that we just received a char */
             serial_receive1(s, &s->tsr, 1);
-        } else if (qemu_chr_fe_write(&s->chr, &s->tsr, 1) != 1 &&
+        } else if (qemu_chr_fe_write(&s->chr, &s->tsr, 1) == 0 &&
                    s->tsr_retry < MAX_XMIT_RETRY) {
             assert(s->watch_tag == 0);
             s->watch_tag =