From d52cce510db9068f5a12daed78f257b64d247a6d Mon Sep 17 00:00:00 2001
From: Mike Black W9MDB <mdblack98@yahoo.com>
Date: Mon, 16 Aug 2021 22:49:36 -0500
Subject: [PATCH] Add fallback serial open logic to hopefully cure serial port
 open error with K4 https://github.com/Hamlib/Hamlib/issues/768

---
 src/serial.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/serial.c b/src/serial.c
index af7aa518f..dca8c78c8 100644
--- a/src/serial.c
+++ b/src/serial.c
@@ -225,6 +225,21 @@ int HAMLIB_API serial_open(hamlib_port_t *rp)
      * Open in Non-blocking mode. Watch for EAGAIN errors!
      */
     fd = OPEN(rp->pathname, O_RDWR | O_NOCTTY | O_NDELAY);
+    if (fd == -1)
+    {
+        rig_debug(RIG_DEBUG_WARN, "%s: open failed...trying withoud O_NOCTTY\n", __func__);
+        fd = OPEN(rp->pathname, O_RDWR | O_NDELAY);
+    }
+    if (fd == -1)
+    {
+        rig_debug(RIG_DEBUG_WARN, "%s: open failed...trying withoud O_NDELAY\n", __func__);
+        fd = OPEN(rp->pathname, O_RDWR | O_NOCTTY );
+    }
+    if (fd == -1)
+    {
+        rig_debug(RIG_DEBUG_WARN, "%s: open failed...trying withoud O_NDELAY and O_NOCTTY\n", __func__);
+        fd = OPEN(rp->pathname, O_RDWR);
+    }
 
     if (fd == -1)
     {