From 4f4649d0464cfd67ccd5bb48013785612f9ceccf Mon Sep 17 00:00:00 2001
From: bubnikv <bubnikv@gmail.com>
Date: Mon, 21 May 2018 14:33:48 +0200
Subject: [PATCH] avrdude: Fix serial I/O timeout on Windows

---
 xs/src/avrdude/ser_win32.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/xs/src/avrdude/ser_win32.c b/xs/src/avrdude/ser_win32.c
index a284774c2..b1f161291 100644
--- a/xs/src/avrdude/ser_win32.c
+++ b/xs/src/avrdude/ser_win32.c
@@ -90,8 +90,10 @@ static BOOL serial_w32SetTimeOut(HANDLE hComPort, DWORD timeout) // in ms
 {
 	COMMTIMEOUTS ctmo;
 	ZeroMemory (&ctmo, sizeof(COMMTIMEOUTS));
-	ctmo.ReadIntervalTimeout = timeout;
-	ctmo.ReadTotalTimeoutMultiplier = timeout;
+	// Don't use the two other two values, set them to zero. This way a constant timeout is used
+	// for the following reads.
+	// ctmo.ReadIntervalTimeout = timeout;
+	// ctmo.ReadTotalTimeoutMultiplier = timeout;
 	ctmo.ReadTotalTimeoutConstant = timeout;
 
 	return SetCommTimeouts(hComPort, &ctmo);