From da7669f3dc665cb1da26c8c46c5d677ba9c112c6 Mon Sep 17 00:00:00 2001
From: stefanrueger <stefan.rueger@urclocks.com>
Date: Tue, 13 May 2025 00:18:14 +0200
Subject: [PATCH 1/2] Fix r/w timeout for Windows ser_send()

---
 src/ser_win32.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/ser_win32.c b/src/ser_win32.c
index 8a53ad46..d3f7f414 100644
--- a/src/ser_win32.c
+++ b/src/ser_win32.c
@@ -81,6 +81,15 @@ static BOOL serial_w32SetTimeOut(HANDLE hComPort, DWORD timeout) { // ms
   return SetCommTimeouts(hComPort, &ctmo);
 }
 
+static BOOL serial_w32SetRWTimeOut(HANDLE hComPort, DWORD timeout) { // ms
+  COMMTIMEOUTS ctmo = {0};
+
+  ctmo.ReadTotalTimeoutConstant = timeout;
+  ctmo.WriteTotalTimeoutConstant = timeout;
+
+  return SetCommTimeouts(hComPort, &ctmo);
+}
+
 static int ser_setparams(const union filedescriptor *fd, long baud, unsigned long cflags) {
   if(cx->ser_serial_over_ethernet)
     return -ENOTTY;
@@ -343,7 +352,10 @@ static int ser_send(const union filedescriptor *fd, const unsigned char *buf, si
   if(verbose >= MSG_TRACE)
     trace_buffer(__func__, buf, len);
 
-  serial_w32SetTimeOut(hComPort, 500);
+  if(!serial_w32SetRWTimeOut(hComPort, (len > 5? len: 5)*100)) {
+    pmsg_error("cannot set r/w timeout for serial port\n");
+    return -1;
+  }
 
   if(!WriteFile(hComPort, buf, len, &written, NULL)) {
     pmsg_error("unable to write: %s\n", "sorry no info avail"); // TODO

From e9d58b5f30000cc31fa72765778796691e784bca Mon Sep 17 00:00:00 2001
From: stefanrueger <stefan.rueger@urclocks.com>
Date: Tue, 13 May 2025 13:16:47 +0200
Subject: [PATCH 2/2] Increase windows serial timeouts for 110 baud or more

---
 src/ser_win32.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/ser_win32.c b/src/ser_win32.c
index d3f7f414..b9333d48 100644
--- a/src/ser_win32.c
+++ b/src/ser_win32.c
@@ -70,7 +70,8 @@ static DWORD serial_baud_lookup(long baud) {
   return baud;
 }
 
-static BOOL serial_w32SetTimeOut(HANDLE hComPort, DWORD timeout) { // ms
+// Set read timeout in ms
+static BOOL serial_w32SetTimeOut(HANDLE hComPort, DWORD timeout) {
   COMMTIMEOUTS ctmo;
 
   ZeroMemory(&ctmo, sizeof(COMMTIMEOUTS));
@@ -81,7 +82,8 @@ static BOOL serial_w32SetTimeOut(HANDLE hComPort, DWORD timeout) { // ms
   return SetCommTimeouts(hComPort, &ctmo);
 }
 
-static BOOL serial_w32SetRWTimeOut(HANDLE hComPort, DWORD timeout) { // ms
+// Set read/write timeout in ms
+static BOOL serial_w32SetRWTimeOut(HANDLE hComPort, DWORD timeout) {
   COMMTIMEOUTS ctmo = {0};
 
   ctmo.ReadTotalTimeoutConstant = timeout;
@@ -352,7 +354,8 @@ static int ser_send(const union filedescriptor *fd, const unsigned char *buf, si
   if(verbose >= MSG_TRACE)
     trace_buffer(__func__, buf, len);
 
-  if(!serial_w32SetRWTimeOut(hComPort, (len > 5? len: 5)*100)) {
+  // Set minimum r/w timeout to 2000 ms or higher to cater for 110 baud or faster
+  if(!serial_w32SetRWTimeOut(hComPort, (len > 20? len: 20)*100)) {
     pmsg_error("cannot set r/w timeout for serial port\n");
     return -1;
   }
@@ -445,7 +448,12 @@ static int ser_recv(const union filedescriptor *fd, unsigned char *buf, size_t b
     return -1;
   }
 
-  serial_w32SetTimeOut(hComPort, serial_recv_timeout);
+  // Ensure can receive buflen bytes at 8N1 at 110 baud or higher: one byte takes 91 ms at 110 baud
+  long timeout = (long) buflen*100 > serial_recv_timeout? (long) buflen*100: serial_recv_timeout;
+  if(!serial_w32SetTimeOut(hComPort, timeout)) {
+    pmsg_error("cannot set read timeout for serial port\n");
+    return -1;
+  }
 
   if(!ReadFile(hComPort, buf, buflen, &read, NULL)) {
     LPVOID lpMsgBuf;
@@ -553,9 +561,8 @@ static int ser_drain(const union filedescriptor *fd, int display) {
 
   serial_w32SetTimeOut(hComPort, serial_drain_timeout);
 
-  if(display) {
+  if(display)
     msg_info("drain>");
-  }
 
   while(1) {
     readres = ReadFile(hComPort, buf, 1, &read, NULL);