More efficient baud hunting -- always start at the last successful speed,

hunt only if that doesn't match.

4 files changed, 47 insertions, 41 deletions

diff --git a/gpsd.h b/gpsd.h
index 2943c66b..b8479664 100644
--- a/gpsd.h
+++ b/gpsd.h
@@ -84,8 +84,8 @@ extern int nmea_send(int fd, const char *fmt, ... );
 extern int nmea_sane_satellites(struct gps_data_t *out);
 extern void nmea_add_checksum(char *sentence);
 extern int nmea_validate_buffer(char *buf, size_t n);
-extern int gpsd_open(int device_speed, int stopbits, struct gps_session_t *context);
-extern int gpsd_set_speed(struct gps_session_t *session, int speed);
+extern int gpsd_open(struct gps_session_t *context);
+extern int gpsd_set_speed(struct gps_session_t *session, unsigned int speed);
 extern int gpsd_get_speed(struct termios *);
 extern void gpsd_drain(int ttyfd);
 extern void gpsd_close(struct gps_session_t *context);
diff --git a/gpsd.py b/gpsd.py
index b99e665d..3c3bd723 100755
--- a/gpsd.py
+++ b/gpsd.py
@@ -302,11 +302,12 @@ class gpsd(gps.gpsdata):
         return buf
 
     def set_speed(self, speed):
-        self.raw[4] = self.raw[5] = eval("termios.B" + `speed`)
-        termios.tcflush(self.ttyfd, termios.TCIOFLUSH)
-        termios.tcsetattr(self.ttyfd, termios.TCSANOW, self.raw)
-        termios.tcflush(self.ttyfd, termios.TCIOFLUSH)
-        time.sleep(1)
+        if self.bps != speed:
+            self.raw[4] = self.raw[5] = eval("termios.B" + `speed`)
+            termios.tcflush(self.ttyfd, termios.TCIOFLUSH)
+            termios.tcsetattr(self.ttyfd, termios.TCSANOW, self.raw)
+            termios.tcflush(self.ttyfd, termios.TCIOFLUSH)
+            time.sleep(3)
         if self.readline().find("$GP") > -1:
             self.bps = speed
             return 1
@@ -331,17 +332,14 @@ class gpsd(gps.gpsdata):
             self.raw[2] |= (termios.CSIZE & termios.CS8)	# cflag
         self.raw[2] |= termios.CREAD | termios.CLOCAL		# cflag
         self.raw[3] = 0						# lflag
-        if self.bps:
-            if not self.set_speed(self.bps):
-                self.ttyfd = -1
-                return -1
-        else:
+        if self.bps and not self.set_speed(self.bps):
             for speed in (4800, 9600, 19200, 38400, 57600):
-                if self.set_speed(speed):
-                    break
+                if speed != self.bps:
+                    if self.set_speed(speed):
+                        break
             else:
                 self.ttyfd = -1
-                return -1
+                return self.ttyfd
         if self.devtype.initializer:
             self.devtype.initializer(self)
 	self.online = True;
diff --git a/libgpsd_core.c b/libgpsd_core.c
index 24d0b2b7..39f8af8e 100644
--- a/libgpsd_core.c
+++ b/libgpsd_core.c
@@ -88,7 +88,7 @@ void gpsd_deactivate(struct gps_session_t *session)
 int gpsd_activate(struct gps_session_t *session)
 /* acquire a connection to the GPS device */
 {
-    if (gpsd_open(session->gNMEAdata.baudrate, session->device_type->stopbits, session) < 0)
+    if (gpsd_open(session) < 0)
 	return -1;
     else {
 	tcflush(session->gNMEAdata.gps_fd, TCIOFLUSH);	/* ignore old sentences */
diff --git a/serial.c b/serial.c
index a31d7e4f..5c521a33 100644
--- a/serial.c
+++ b/serial.c
@@ -36,10 +36,10 @@ int gpsd_get_speed(struct termios* ttyctl)
 /* every rate we're likely to see on a GPS */
 static int rates[] = {4800, 9600, 19200, 38400, 57600};
 
-int gpsd_set_speed(struct gps_session_t *session, int speed)
+int gpsd_set_speed(struct gps_session_t *session, unsigned int speed)
 {
     char	buf[NMEA_MAX+1];
-    unsigned int	n, rate;
+    unsigned int	n, rate, ok;
 
     if (speed < 300)
 	rate = 0;
@@ -60,31 +60,38 @@ int gpsd_set_speed(struct gps_session_t *session, int speed)
     else
       rate =  B57600;
 
-    tcflush(session->gNMEAdata.gps_fd, TCIOFLUSH);
-    cfsetispeed(&session->ttyset, (speed_t)rate);
-    cfsetospeed(&session->ttyset, (speed_t)rate);
-    if (tcsetattr(session->gNMEAdata.gps_fd, TCSANOW, &session->ttyset) != 0)
-	return 0;
-    tcflush(session->gNMEAdata.gps_fd, TCIOFLUSH);
+    if (speed != cfgetispeed(&session->ttyset)) {
+	tcflush(session->gNMEAdata.gps_fd, TCIOFLUSH);
+	cfsetispeed(&session->ttyset, (speed_t)rate);
+	cfsetospeed(&session->ttyset, (speed_t)rate);
+	if (tcsetattr(session->gNMEAdata.gps_fd, TCSANOW, &session->ttyset) != 0)
+	    return 0;
+	tcflush(session->gNMEAdata.gps_fd, TCIOFLUSH);
 
-    usleep(1250000);	/* allow the UART time to settle */
+	usleep(3000000);	/* allow the UART time to settle */
+    }
 
     if (session->device_type->validate_buffer) {
 	n = 0;
 	while (n < NMEA_MAX) {
 	    n += read(session->gNMEAdata.gps_fd, buf+n, sizeof(buf)-n-1);
+	    if (n > 2 && buf[n-2] == '\r' && buf[n-1] == '\n')
+		break;
 	}
 	gpsd_report(4, "validating %d bytes.\n", n);
-	return session->device_type->validate_buffer(buf, n);
+	ok = session->device_type->validate_buffer(buf, n);
     } else {
 	/* this has the effect of disabling baud hunting on future connects */
 	gpsd_report(4, "no buffer validation.\n");
-	session->gNMEAdata.baudrate = speed;
-	return 1;
+	ok = 1;
     }
+
+    if (ok)
+	session->gNMEAdata.baudrate = speed;
+    return ok;
 }
 
-int gpsd_open(int device_speed, int stopbits, struct gps_session_t *session)
+int gpsd_open(struct gps_session_t *session)
 {
     int *ip;
 
@@ -103,25 +110,26 @@ int gpsd_open(int device_speed, int stopbits, struct gps_session_t *session)
 	 * in the presence of flow control.  Thus, turn off CRTSCTS.
 	 */
 	session->ttyset.c_cflag &= ~(PARENB | CRTSCTS);
-	session->ttyset.c_cflag |= (CSIZE & (stopbits==2 ? CS7 : CS8)) | CREAD | CLOCAL;
+	session->ttyset.c_cflag |= (CSIZE & (session->gNMEAdata.stopbits==2 ? CS7 : CS8)) | CREAD | CLOCAL;
 	session->ttyset.c_iflag = session->ttyset.c_oflag = session->ttyset.c_lflag = (tcflag_t) 0;
 	session->ttyset.c_oflag = (ONLCR);
 
-	if (device_speed) {
+	if (session->gNMEAdata.baudrate) {
 	    gpsd_report(1, "setting speed %d, %d stopbits, no parity\n", 
-			device_speed, stopbits);
-	    if (gpsd_set_speed(session, device_speed)) {
+			session->gNMEAdata.baudrate, 
+			session->gNMEAdata.stopbits);
+	    if (gpsd_set_speed(session, session->gNMEAdata.baudrate)) {
 		return session->gNMEAdata.gps_fd;
 	    }
-	} else
-	    for (ip = rates; ip < rates + sizeof(rates)/sizeof(rates[0]); ip++) {
-		gpsd_report(1, "hunting at speed %d, %d stopbits, no parity\n", 
-			    *ip, stopbits);
-		if (gpsd_set_speed(session, *ip)) {
+	}
+	for (ip = rates; ip < rates + sizeof(rates)/sizeof(rates[0]); ip++) 
+	    if (*ip != session->gNMEAdata.baudrate) {
+		gpsd_report(1, "hunting at speed %d, %d stopbits, no parity\n",
+			    *ip, session->gNMEAdata.stopbits);
+		if (gpsd_set_speed(session, *ip))
 		    return session->gNMEAdata.gps_fd;
-		}
-	    }
-	return -1;
+	}
+	session->gNMEAdata.gps_fd = -1;
     }
     return session->gNMEAdata.gps_fd;
 }