serialport_write could loop endlessly when used with a seemingly valid port
that does always return 0 on writes instead of an error.
Give up after about 125 ms i.e. 250 tries with a period of 500 us.
Signed-off-by: Stefan Tauner <stefan.tauner(a)student.tuwien.ac.at>
---
serial.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/serial.c b/serial.c
index 7e47dcc..794763e 100644
--- a/serial.c
+++ b/serial.c
@@ -262,6 +262,7 @@ int serialport_write(unsigned char *buf, unsigned int writecnt)
#else
ssize_t tmp = 0;
#endif
+ unsigned int empty_writes = 250; /* results in a ca. 125ms timeout */
while (writecnt > 0) {
#ifdef _WIN32
@@ -273,9 +274,16 @@ int serialport_write(unsigned char *buf, unsigned int writecnt)
msg_perr("Serial port write error!\n");
return 1;
}
- if (!tmp)
- msg_pdbg("Empty write\n");
- writecnt -= tmp;
+ if (!tmp) {
+ msg_pdbg2("Empty write\n");
+ empty_writes--;
+ programmer_delay(500);
+ if (empty_writes == 0) {
+ msg_perr("Serial port seems dead!\n");
+ return 1;
+ }
+ }
+ writecnt -= tmp;
buf += tmp;
}
--
Kind regards, Stefan Tauner