From 5d21340928cd46b3cb97cae0b9c707a71ef9ced0 Mon Sep 17 00:00:00 2001
From: Tero Kontkanen <tero.k@granitedevices.com>
Date: Wed, 16 Aug 2017 16:14:16 -0700
Subject: Sets serial port in low latency mode in Linux

---
 pcserialport.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/pcserialport.c b/pcserialport.c
index 5134a6d..8cbe281 100644
--- a/pcserialport.c
+++ b/pcserialport.c
@@ -25,6 +25,11 @@
 #include <sys/types.h>
 #include <string.h>
 
+#if defined(__linux__)
+//needed for setting low latency
+#include <linux/serial.h>
+#endif
+
 #if defined(__APPLE__)
 #include <CoreFoundation/CoreFoundation.h>
 #include <IOKit/IOKitLib.h>
@@ -178,6 +183,20 @@ smint32 serialPortOpen(const char * port_device_name, smint32 baudrate_bps)
         return -1;
     }
     #endif
+    
+    #if defined(TIOCGSERIAL) && defined(ASYNC_LOW_LATENCY)
+    struct serial_struct serial; 
+    if(ioctl(port_handle, TIOCGSERIAL, &serial)!=-1)
+    {
+        serial.flags |= ASYNC_LOW_LATENCY;
+        if(ioctl(port_handle, TIOCSSERIAL, &serial) == -1 )
+        {
+            smDebug(-1, Low, "Serial port warning: unable to set low latency mode, maybe try running with root permissions.");
+        }
+    }
+    else
+        smDebug(-1, Low, "Serial port warning: unable to read TIOCGSERIAL for low latency mode, maybe try running with root permissions.");
+    #endif
 
     //flush any stray bytes from device receive buffer that may reside in it
     //note: according to following page, delay before this may be necessary http://stackoverflow.com/questions/13013387/clearing-the-serial-ports-buffer
-- 
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