serial: Be careful with comparison of transmit_max to transmit_pos

There is a small possibility that a shutdown could occur between
clearing transmit_max and clearing transmit_pos - so make sure to
handle the case where transmit_pos > transmit_max.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/avr/serial.c b/src/avr/serial.c
index 8c0da553..0b5fea1f 100644
--- a/src/avr/serial.c
+++ b/src/avr/serial.c
@@ -115,7 +115,7 @@ char *
 console_get_output(uint8_t len)
 {
     uint8_t tpos = readb(&transmit_pos), tmax = readb(&transmit_max);
-    if (tpos == tmax) {
+    if (tpos >= tmax) {
         tpos = tmax = 0;
         writeb(&transmit_max, 0);
         writeb(&transmit_pos, 0);