Major rearrangement of device members in struct gpsdata_t...

...documented in the protocol-transition white paper.  All regression
tests pass.

21 files changed, 199 insertions, 183 deletions

diff --git a/driver_evermore.c b/driver_evermore.c
index 60a8e11d..cb159e56 100644
--- a/driver_evermore.c
+++ b/driver_evermore.c
@@ -382,7 +382,7 @@ static bool evermore_speed(struct gps_device_t *session,
     /*@ -type @*/
     gpsd_report(LOG_PROG, "evermore_speed(%d%c%d)\n", speed, parity, stopbits);
     /* parity and stopbit switching aren't available on this chip */
-    if (parity!=(int)session->gpsdata.parity || stopbits!=(int)session->gpsdata.parity) {
+    if (parity!=(int)session->gpsdata.dev.parity || stopbits!=(int)session->gpsdata.dev.parity) {
 	return false;
     } else {
 	unsigned char tmp8;
@@ -457,13 +457,13 @@ static void evermore_mode(struct gps_device_t *session, int mode)
     if (mode == MODE_NMEA) {
         /* NMEA */
         (void) evermore_protocol(session, 1);
-        session->gpsdata.driver_mode = MODE_NMEA;
+        session->gpsdata.dev.driver_mode = MODE_NMEA;
         (void) evermore_nmea_config(session, 1); /* configure NMEA messages for gpsd */
     } else {
         /* binary */
         (void) evermore_protocol(session, 0);
         session->back_to_nmea = false;
-        session->gpsdata.driver_mode = MODE_BINARY;
+        session->gpsdata.dev.driver_mode = MODE_BINARY;
     }
 }
 
diff --git a/driver_italk.c b/driver_italk.c
index 3f8de031..6bf17445 100644
--- a/driver_italk.c
+++ b/driver_italk.c
@@ -315,12 +315,12 @@ static gps_mask_t italk_parse_input(struct gps_device_t *session)
 
     if (session->packet.type == ITALK_PACKET){
 	st = italk_parse(session, session->packet.outbuffer, session->packet.outbuflen);
-	session->gpsdata.driver_mode = MODE_BINARY;	/* binary */
+	session->gpsdata.dev.driver_mode = MODE_BINARY;	/* binary */
 	return st;
 #ifdef NMEA_ENABLE
     } else if (session->packet.type == NMEA_PACKET) {
 	st = nmea_parse((char *)session->packet.outbuffer, session);
-	session->gpsdata.driver_mode = MODE_NMEA;	/* NMEA */
+	session->gpsdata.dev.driver_mode = MODE_NMEA;	/* NMEA */
 	return st;
 #endif /* NMEA_ENABLE */
     } else
@@ -377,9 +377,9 @@ static void italk_mode(struct gps_device_t *session,  int mode)
 {
     if (mode == MODE_NMEA) {
 	(void)italk_set_mode(session, 
-			     session->gpsdata.baudrate,
-			     (char)session->gpsdata.parity,
-			     (int)session->gpsdata.stopbits,
+			     session->gpsdata.dev.baudrate,
+			     (char)session->gpsdata.dev.parity,
+			     (int)session->gpsdata.dev.stopbits,
 			     false);
     }
 }
@@ -388,9 +388,9 @@ static void italk_configurator(struct gps_device_t *session, unsigned int seq)
 {
     if (seq == 0 && session->packet.type == NMEA_PACKET)
 	(void)italk_set_mode(session, 
-			     session->gpsdata.baudrate, 
-			     (char)session->gpsdata.parity,
-			     (int)session->gpsdata.stopbits,
+			     session->gpsdata.dev.baudrate, 
+			     (char)session->gpsdata.dev.parity,
+			     (int)session->gpsdata.dev.stopbits,
 			     true);
 }
 #endif /* ALLOW_RECONFIGURE */
diff --git a/driver_navcom.c b/driver_navcom.c
index 02832fdf..5ab00a33 100644
--- a/driver_navcom.c
+++ b/driver_navcom.c
@@ -1146,12 +1146,12 @@ static gps_mask_t navcom_parse_input(struct gps_device_t *session)
 
     if (session->packet.type == NAVCOM_PACKET){
 	st = navcom_parse(session, session->packet.outbuffer, session->packet.outbuflen);
-	session->gpsdata.driver_mode = MODE_BINARY;  /* binary */
+	session->gpsdata.dev.driver_mode = MODE_BINARY;  /* binary */
 	return st;
 #ifdef NMEA_ENABLE
     } else if (session->packet.type == NMEA_PACKET) {
 	st = nmea_parse((char *)session->packet.outbuffer, session);
-	session->gpsdata.driver_mode = MODE_NMEA;  /* NMEA */
+	session->gpsdata.dev.driver_mode = MODE_NMEA;  /* NMEA */
 	return st;
 #endif /* NMEA_ENABLE */
     } else
@@ -1184,7 +1184,7 @@ static bool navcom_speed(struct gps_device_t *session,
 			 unsigned int speed, char parity, int stopbits)
 {
     /* parity and stopbit switching aren't implemented */
-    if (parity!=(char)session->gpsdata.parity || stopbits!=(int)session->gpsdata.parity) {
+    if (parity!=(char)session->gpsdata.dev.parity || stopbits!=(int)session->gpsdata.dev.parity) {
 	return false;
     } else {
 	u_int8_t port_selection;
diff --git a/driver_oncore.c b/driver_oncore.c
index 4ee3cbc5..3bc6e6f1 100644
--- a/driver_oncore.c
+++ b/driver_oncore.c
@@ -402,12 +402,12 @@ static gps_mask_t oncore_parse_input(struct gps_device_t *session)
 
     if (session->packet.type == ONCORE_PACKET){
 	st = oncore_dispatch(session, session->packet.outbuffer, session->packet.outbuflen);
-	session->gpsdata.driver_mode = MODE_BINARY;
+	session->gpsdata.dev.driver_mode = MODE_BINARY;
 	return st;
 #ifdef NMEA_ENABLE
     } else if (session->packet.type == NMEA_PACKET) {
 	st = nmea_parse((char *)session->packet.outbuffer, session);
-	session->gpsdata.driver_mode = MODE_NMEA;
+	session->gpsdata.dev.driver_mode = MODE_NMEA;
 	return st;
 #endif /* NMEA_ENABLE */
     } else
@@ -435,7 +435,7 @@ static void oncore_set_mode(struct gps_device_t *session, int mode)
     if (mode == MODE_NMEA) {
 	/* send the mode switch control string */
 	/* oncore_to_nmea(session->gpsdata.gps_fd,session->gpsdata.baudrate);*/
-	session->gpsdata.driver_mode = MODE_NMEA;
+	session->gpsdata.dev.driver_mode = MODE_NMEA;
 	/* 
 	 * Anticipatory switching works only when the packet getter is the
 	 * generic one and it recognizes packets of the type this driver 
@@ -444,7 +444,7 @@ static void oncore_set_mode(struct gps_device_t *session, int mode)
 	(void)gpsd_switch_driver(session, "Generic NMEA");
     } else {
 	session->back_to_nmea = false;
-	session->gpsdata.driver_mode = MODE_BINARY;
+	session->gpsdata.dev.driver_mode = MODE_BINARY;
     }
 }
 
diff --git a/driver_sirf.c b/driver_sirf.c
index 338b76ad..dd19ab20 100644
--- a/driver_sirf.c
+++ b/driver_sirf.c
@@ -207,7 +207,7 @@ static bool sirf_to_nmea(int ttyfd, speed_t speed)
 static void sirfbin_mode(struct gps_device_t *session, int mode)
 {
     if (mode == MODE_NMEA) {
-	(void)sirf_to_nmea(session->gpsdata.gps_fd,session->gpsdata.baudrate);
+	(void)sirf_to_nmea(session->gpsdata.gps_fd,session->gpsdata.dev.baudrate);
     } else {
 	session->back_to_nmea = false;
     }
@@ -219,9 +219,9 @@ static ssize_t sirf_get(struct gps_device_t *session)
     ssize_t len = generic_get(session);
 
     if (session->packet.type == SIRF_PACKET) {
-	session->gpsdata.driver_mode = MODE_BINARY;
+	session->gpsdata.dev.driver_mode = MODE_BINARY;
     } else if (session->packet.type == NMEA_PACKET) {
-	session->gpsdata.driver_mode = MODE_NMEA;
+	session->gpsdata.dev.driver_mode = MODE_NMEA;
 	(void)gpsd_switch_driver(session, "Generic NMEA");
     } else {
 	/* should never happen */
@@ -310,7 +310,7 @@ static gps_mask_t sirf_msg_swversion(struct gps_device_t *session, unsigned char
 #ifdef NTPSHM_ENABLE
     session->driver.sirf.time_seen = 0;
 #endif /* NTPSHM_ENABLE */
-    if (session->gpsdata.baudrate >= 38400){
+    if (session->gpsdata.dev.baudrate >= 38400){
 	gpsd_report(LOG_PROG, "Enabling subframe transmission...\n");
 	(void)sirf_write(session->gpsdata.gps_fd, enablesubframe);
     }
@@ -348,7 +348,7 @@ static gps_mask_t sirf_msg_navdata(struct gps_device_t *session, unsigned char *
     gpsd_interpret_subframe(session, words);
 
 #ifdef ALLOW_RECONFIGURE
-    if (session->gpsdata.baudrate < 38400){
+    if (session->gpsdata.dev.baudrate < 38400){
 	gpsd_report(LOG_PROG, "Disabling subframe transmission...\n");
 	(void)sirf_write(session->gpsdata.gps_fd, disablesubframe);
     }
@@ -884,12 +884,12 @@ static gps_mask_t sirfbin_parse_input(struct gps_device_t *session)
     if (session->packet.type == SIRF_PACKET){
 	st = sirf_parse(session, session->packet.outbuffer,
 			session->packet.outbuflen);
-	session->gpsdata.driver_mode = MODE_BINARY;
+	session->gpsdata.dev.driver_mode = MODE_BINARY;
 	return st;
 #ifdef NMEA_ENABLE
     } else if (session->packet.type == NMEA_PACKET) {
 	st = nmea_parse((char *)session->packet.outbuffer, session);
-	session->gpsdata.driver_mode = MODE_NMEA;
+	session->gpsdata.dev.driver_mode = MODE_NMEA;
 	return st;
 #endif /* NMEA_ENABLE */
     } else
@@ -904,7 +904,7 @@ static void sirfbin_configure(struct gps_device_t *session, unsigned int seq)
     if (session->packet.type == NMEA_PACKET) {
 	gpsd_report(LOG_PROG, "Switching chip mode to SiRF binary.\n");
 	(void)nmea_send(session,
-		  "$PSRF100,0,%d,8,1,0", session->gpsdata.baudrate);
+		  "$PSRF100,0,%d,8,1,0", session->gpsdata.dev.baudrate);
     }
     /* do this every time*/
     {
diff --git a/driver_superstar2.c b/driver_superstar2.c
index d4a5a9b0..f95197f6 100644
--- a/driver_superstar2.c
+++ b/driver_superstar2.c
@@ -535,13 +535,13 @@ static gps_mask_t superstar2_parse_input(struct gps_device_t *session)
     if (session->packet.type == SUPERSTAR2_PACKET){
 	st = superstar2_dispatch(session, session->packet.outbuffer,
 				 session->packet.length);
-	session->gpsdata.driver_mode = MODE_BINARY;
+	session->gpsdata.dev.driver_mode = MODE_BINARY;
 	return st;
 #ifdef NMEA_ENABLE
     } else if (session->packet.type == NMEA_PACKET) {
 	st = nmea_parse((char *)session->packet.outbuffer, session);
 	(void)gpsd_switch_driver(session, "Generic NMEA");
-	session->gpsdata.driver_mode = MODE_NMEA;
+	session->gpsdata.dev.driver_mode = MODE_NMEA;
 	return st;
 #endif /* NMEA_ENABLE */
     } else
@@ -569,7 +569,7 @@ static bool superstar2_set_speed(struct gps_device_t *session,
 				 speed_t speed, char parity, int stopbits)
 {
      /* parity and stopbit switching aren't available on this chip */
-    if (parity!=(char)session->gpsdata.parity || (unsigned int)stopbits!=session->gpsdata.stopbits) {
+    if (parity!=(char)session->gpsdata.dev.parity || (unsigned int)stopbits!=session->gpsdata.dev.stopbits) {
 	return false;
     } else {
 	/*@ +charint @*/
@@ -590,7 +590,7 @@ static void superstar2_set_mode(struct gps_device_t *session, int mode)
 	char mode_msg[] = {0x01, 0x48, 0xB7, 0x01, 0x00, 0x00, 0x00};
 
 	/* high bit 0 in the mode word means set NMEA mode */
-	mode_msg[4] = (char)(session->gpsdata.baudrate / 300);
+	mode_msg[4] = (char)(session->gpsdata.dev.baudrate / 300);
 	(void)superstar2_write(session, mode_msg, 7);
 	/*@ -charint @*/
     } else {
diff --git a/driver_tsip.c b/driver_tsip.c
index 6d301063..d20fadb7 100644
--- a/driver_tsip.c
+++ b/driver_tsip.c
@@ -59,9 +59,9 @@ static void tsip_probe_subtype(struct gps_device_t *session, unsigned int seq)
 	/* XXX Thunderbolts and Copernicus use 8N1... which isn't exactly a */
 	/* XXX good idea due to the fragile wire format.   We must divine a */
 	/* XXX clever heuristic to decide if the parity change is required. */
-	session->driver.tsip.parity = session->gpsdata.parity;
-	session->driver.tsip.stopbits = session->gpsdata.stopbits;
-	gpsd_set_speed(session, session->gpsdata.baudrate, 'O', 1);
+	session->driver.tsip.parity = session->gpsdata.dev.parity;
+	session->driver.tsip.stopbits = session->gpsdata.dev.stopbits;
+	gpsd_set_speed(session, session->gpsdata.dev.baudrate, 'O', 1);
 	break;
 
     case 1:
@@ -85,7 +85,7 @@ static void tsip_wrapup(struct gps_device_t *session)
 {
     /* restore saved parity and stopbits when leaving TSIP mode */
     gpsd_set_speed(session,
-		   session->gpsdata.baudrate,
+		   session->gpsdata.dev.baudrate,
 		   (unsigned char)session->driver.tsip.parity,
 		   session->driver.tsip.stopbits);
 }
@@ -763,13 +763,13 @@ static gps_mask_t tsip_parse_input(struct gps_device_t *session)
 
     if (session->packet.type == TSIP_PACKET){
 	st = tsip_analyze(session);
-	session->gpsdata.driver_mode = MODE_BINARY;
+	session->gpsdata.dev.driver_mode = MODE_BINARY;
 	return st;
 #ifdef EVERMORE_ENABLE
     } else if (session->packet.type == EVERMORE_PACKET) {
 	(void)gpsd_switch_driver(session, "EverMore binary");
 	st = evermore_parse(session, session->packet.outbuffer, session->packet.outbuflen);
-	session->gpsdata.driver_mode = MODE_BINARY;
+	session->gpsdata.dev.driver_mode = MODE_BINARY;
 	return st;
 #endif /* EVERMORE_ENABLE */
     } else
@@ -824,7 +824,7 @@ static bool tsip_speed_switch(struct gps_device_t *session,
     }
 
     putbyte(buf,0,0xff);		/* current port */
-    putbyte(buf,1,(round(log((double)speed/300)/M_LN2))+2); /* input baudrate */
+    putbyte(buf,1,(round(log((double)speed/300)/M_LN2))+2); /* input dev.baudrate */
     putbyte(buf,2,getub(buf,1));	/* output baudrate */
     putbyte(buf,3,3);			/* character width (8 bits) */
     putbyte(buf,4,parity);		/* parity (normally odd) */
diff --git a/driver_ubx.c b/driver_ubx.c
index 9f2ce882..d5f6aae3 100644
--- a/driver_ubx.c
+++ b/driver_ubx.c
@@ -469,12 +469,12 @@ static gps_mask_t parse_input(struct gps_device_t *session)
 
     if (session->packet.type == UBX_PACKET){
 	st = ubx_parse(session, session->packet.outbuffer, session->packet.outbuflen);
-	session->gpsdata.driver_mode = MODE_BINARY;
+	session->gpsdata.dev.driver_mode = MODE_BINARY;
 	return st;
 #ifdef NMEA_ENABLE
     } else if (session->packet.type == NMEA_PACKET) {
 	st = nmea_parse((char *)session->packet.outbuffer, session);
-	session->gpsdata.driver_mode = MODE_NMEA;
+	session->gpsdata.dev.driver_mode = MODE_NMEA;
 	return st;
 #endif /* NMEA_ENABLE */
     } else
@@ -631,7 +631,7 @@ static void ubx_nmea_mode(struct gps_device_t *session, int mode)
     for(i=0;i<22;i++)
 	buf[i] = original_port_settings[i];	/* copy the original port settings */
     if(buf[0] == 0x01)				/* set baudrate on serial port only */
-	putlelong(buf, 8, session->gpsdata.baudrate);
+	putlelong(buf, 8, session->gpsdata.dev.baudrate);
 
     if (mode == 0) {
 	buf[14] &= ~0x01;			/* turn off UBX output on this port */
diff --git a/drivers.c b/drivers.c
index 4989c048..cc42624b 100644
--- a/drivers.c
+++ b/drivers.c
@@ -154,9 +154,9 @@ static void nmea_probe_subtype(struct gps_device_t *session, unsigned int seq)
 	 */
 	(void)nmea_send(session,
 			"$PSRF100,0,%d,%d,%d,0",
-			session->gpsdata.baudrate,
-			9-session->gpsdata.stopbits,
-			session->gpsdata.stopbits);
+			session->gpsdata.dev.baudrate,
+			9-session->gpsdata.dev.stopbits,
+			session->gpsdata.dev.stopbits);
 	session->back_to_nmea = true;
 	break;
     case 2:
@@ -251,7 +251,7 @@ static void garmin_mode_switch(struct gps_device_t *session, int mode)
 	(void)nmea_send(session, "$PGRMC1,1,2,1,,,,2,W,N");
 	(void)nmea_send(session, "$PGRMI,,,,,,,R");
 	(void)usleep(333);	/* standard Garmin settling time */
-	session->gpsdata.driver_mode = MODE_BINARY;
+	session->gpsdata.dev.driver_mode = MODE_BINARY;
     }
 }
 
diff --git a/gps.h b/gps.h
index 0d119a67..e277bbd9 100644
--- a/gps.h
+++ b/gps.h
@@ -831,6 +831,9 @@ struct device_t {
     char driver[64];
     char subtype[64];
     double activated;
+    unsigned int baudrate, parity, stopbits;	/* RS232 link parameters */
+    double       cycle, mincycle;	/* refresh cycle time in seconds */
+    unsigned int driver_mode;		/* is driver in native mode or not? */
 };
 
 struct watch_t {
@@ -913,12 +916,7 @@ struct gps_data_t {
     int azimuth[MAXCHANNELS];	/* azimuth */
     double ss[MAXCHANNELS];	/* signal-to-noise ratio (dB) */
 
-    /* where and what gpsd thinks the device is */
-    char	 gps_device[PATH_MAX];	/* only valid if non-null. */
-    char	 *gps_id;		/* only valid if non-null. */
-    unsigned int baudrate, parity, stopbits;	/* RS232 link parameters */
-    double       cycle, mincycle;	/* refresh cycle time in seconds */
-    unsigned int driver_mode;		/* is driver in native mode or not? */
+    struct device_t dev;	/* device that shipped last update */
 
     /* pack things that are never reported together to reduce structure size */ 
     union {
diff --git a/gpsctl.c b/gpsctl.c
index 29f4c336..d089f92b 100644
--- a/gpsctl.c
+++ b/gpsctl.c
@@ -275,7 +275,7 @@ int main(int argc, char **argv)
 	    // FIXME: Requires old protocol
 	    (void)gps_query(gpsdata, "OFIB");
 	    gpsd_report(LOG_SHOUT, "%s identified as %s at %d\n",
-			gpsdata->gps_device,gpsdata->gps_id,gpsdata->baudrate);
+			gpsdata->dev.path,gpsdata->dev.subtype,gpsdata->dev.baudrate);
 	    exit(0);
 	}
 
@@ -287,17 +287,17 @@ int main(int argc, char **argv)
 	    exit(0);
 	}
 
-	if (to_nmea) {
-#ifdef OLDSTYLE_ENABLE
-	    (void)gps_query(gpsdata, "N=0");
-#else
-	    (void)gps_query(gpsdata, "?CONFIGDEV={\"mode\":0}\r\n"); 
-#endif /* OLDSTYLE_ENABLE */
-	    if (gpsdata->driver_mode != MODE_NMEA) {
-		gpsd_report(LOG_ERROR, "%s mode change to NMEA failed\n", gpsdata->gps_device);
+	   if (to_nmea) {
+   #ifdef OLDSTYLE_ENABLE
+	       (void)gps_query(gpsdata, "N=0");
+   #else
+	       (void)gps_query(gpsdata, "?CONFIGDEV={\"mode\":0}\r\n"); 
+   #endif /* OLDSTYLE_ENABLE */
+	       if (gpsdata->dev.driver_mode != MODE_NMEA) {
+		gpsd_report(LOG_ERROR, "%s mode change to NMEA failed\n", gpsdata->dev.path);
 		status = 1;
 	    } else
-		gpsd_report(LOG_PROG, "%s mode change succeeded\n", gpsdata->gps_device);
+		gpsd_report(LOG_PROG, "%s mode change succeeded\n", gpsdata->dev.path);
 	}
 	else if (to_binary) {
 #ifdef OLDSTYLE_ENABLE
@@ -305,11 +305,11 @@ int main(int argc, char **argv)
 #else
 	    (void)gps_query(gpsdata, "?CONFIGDEV={\"mode\":1}\r\n");
 #endif /* OLDSTYLE_ENABLE */
-	    if (gpsdata->driver_mode != MODE_BINARY) {
-		gpsd_report(LOG_ERROR, "%s mode change to native mode failed\n", gpsdata->gps_device);
+	    if (gpsdata->dev.driver_mode != MODE_BINARY) {
+		gpsd_report(LOG_ERROR, "%s mode change to native mode failed\n", gpsdata->dev.path);
 		status = 1;
 	    } else
-		gpsd_report(LOG_PROG, "%s mode change succeeded\n", gpsdata->gps_device);
+		gpsd_report(LOG_PROG, "%s mode change succeeded\n", gpsdata->dev.path);
 	}
 	if (speed != NULL) {
 	    char parity = 'N';
@@ -352,14 +352,14 @@ int main(int argc, char **argv)
 #endif /* OLDSTYLE_ENABLE */
 				    speed, parity, stopbits);
 	    }
-	    if (atoi(speed) != (int)gpsdata->baudrate) {
+	    if (atoi(speed) != (int)gpsdata->dev.baudrate) {
 		gpsd_report(LOG_ERROR, "%s driver won't support %s%c%d\n", 
-			    gpsdata->gps_device,
+			    gpsdata->dev.path,
 			    speed, parity, stopbits);
 		status = 1;
 	    } else
 		gpsd_report(LOG_PROG, "%s change to %s%c%d succeeded\n", 
-			    gpsdata->gps_device,
+			    gpsdata->dev.path,
 			    speed, parity, stopbits);
 	}
 	if (rate != NULL) {
@@ -390,7 +390,7 @@ int main(int argc, char **argv)
 	/*@ -mustfreeonly -immediatetrans @*/
 	session.context = &context;
 	gpsd_tty_init(&session);
-	(void)strlcpy(session.gpsdata.gps_device, device, sizeof(session.gpsdata.gps_device));
+	(void)strlcpy(session.gpsdata.dev.path, device, sizeof(session.gpsdata.dev.path));
 	session.device_type = forcetype;
 	(void)gpsd_open(&session);
 	(void)gpsd_set_raw(&session);
@@ -455,7 +455,7 @@ int main(int argc, char **argv)
 		}
 	    }
 	    gpsd_report(LOG_PROG, "%s looks like a %s at %d.\n",
-			device, gpsd_id(&session), session.gpsdata.baudrate);
+			device, gpsd_id(&session), session.gpsdata.dev.baudrate);
 
 	    if (forcetype!=NULL && strcmp("Generic NMEA", session.device_type->type_name) !=0 && strcmp(forcetype->type_name, session.device_type->type_name)!=0) {
 		gpsd_report(LOG_ERROR, "'%s' doesn't match non-generic type '%s' of selected device.", forcetype->type_name, session.device_type->type_name);
@@ -476,7 +476,7 @@ int main(int argc, char **argv)
 		}
 	    }
 	    gpsd_report(LOG_SHOUT, "%s identified as a %s at %d.\n",
-			device, gpsd_id(&session), session.gpsdata.baudrate);
+			device, gpsd_id(&session), session.gpsdata.dev.baudrate);
 	}
 
 	/* if no control operation was specified, we're done */
@@ -537,13 +537,13 @@ int main(int argc, char **argv)
 		}
 		/*@ -nullpass @*/
 		gpsd_report(LOG_SHOUT, "after mode change, %s looks like a %s at %d.\n",
-			    device, gpsd_id(&session), session.gpsdata.baudrate);
+			    device, gpsd_id(&session), session.gpsdata.dev.baudrate);
 		/*@ +nullpass @*/
 	    }
 	}
 	if (speed) {
-	    char parity = echo ? 'N': session.gpsdata.parity;
-	    int stopbits = echo ? 1 : session.gpsdata.stopbits;
+	    char parity = echo ? 'N': session.gpsdata.dev.parity;
+	    int stopbits = echo ? 1 : session.gpsdata.dev.stopbits;
 	    char *modespec;
 
 	    modespec = strchr(speed, ':');
@@ -586,11 +586,11 @@ int main(int argc, char **argv)
 		    (void)tcdrain(session.gpsdata.gps_fd);
 		    (void)usleep(50000);
 		    gpsd_report(LOG_PROG, "%s change to %s%c%d succeeded\n", 
-			    session.gpsdata.gps_device,
+			    session.gpsdata.dev.path,
 			    speed, parity, stopbits);
 		} else {
 		    gpsd_report(LOG_ERROR, "%s driver won't support %s%c%d.\n",
-				session.gpsdata.gps_device,
+				session.gpsdata.dev.path,
 				speed, parity, stopbits);
 		    status = 1;
 		}
diff --git a/gpsd.c b/gpsd.c
index b5ab68c4..3b67f67f 100644
--- a/gpsd.c
+++ b/gpsd.c
@@ -383,8 +383,8 @@ struct subscriber_t {
 #endif
 #define sub_index(s) (int)((s) - subscribers)
 #define channel_index(s) (int)((s) - channels)
-#define allocated_device(devp)	 ((devp)->gpsdata.gps_device[0] != '\0')
-#define free_device(devp)	 (devp)->gpsdata.gps_device[0] = '\0'
+#define allocated_device(devp)	 ((devp)->gpsdata.dev.path[0] != '\0')
+#define free_device(devp)	 (devp)->gpsdata.dev.path[0] = '\0'
 #define initialized_device(devp) ((devp)->context != NULL)
 
 struct gps_device_t devices[MAXDEVICES];
@@ -587,7 +587,7 @@ static void deactivate_device(struct gps_device_t *device)
 #ifdef GPSDNG_ENABLE
     notify_watchers(device, WATCH_NEWSTYLE, 
 		    "{\"class\":\"DEVICE\",\"name\":\"%s\",\"activated\":0}\r\n",
-		    device->gpsdata.gps_device);
+		    device->gpsdata.dev.path);
 #endif /* GPSDNG_ENABLE */
     if (device->gpsdata.gps_fd != -1) {
 	gpsd_deactivate(device);
@@ -609,7 +609,7 @@ static void raw_hook(struct gps_data_t *ud,
 
 	    /* copy raw NMEA sentences from GPS to clients in raw mode */
 	    if (sub != NULL && channel->device != NULL &&
-		strcmp(ud->gps_device, channel->device->gpsdata.gps_device)==0)
+		strcmp(ud->dev.path, channel->device->gpsdata.dev.path)==0)
 		(void)throttled_write(sub, sentence, (ssize_t)len);
 	    
 	}
@@ -622,7 +622,7 @@ static void raw_hook(struct gps_data_t *ud,
     struct gps_device_t *devp;
 
     for (devp = devices; devp < devices + MAXDEVICES; devp++)
-	if (allocated_device(devp) && strcmp(devp->gpsdata.gps_device, device_name)==0)
+	if (allocated_device(devp) && strcmp(devp->gpsdata.dev.path, device_name)==0)
 	    return devp;
     return NULL;
 }
@@ -647,7 +647,7 @@ static /*@null@*/ struct gps_device_t *open_device(char *device_name)
 
     /* normal case: set up GPS/RTCM/AIS service */
     for (devp = devices; devp < devices + MAXDEVICES; devp++)
-	if (!allocated_device(devp) || (strcmp(devp->gpsdata.gps_device, device_name)==0 && !initialized_device(devp))){
+	if (!allocated_device(devp) || (strcmp(devp->gpsdata.dev.path, device_name)==0 && !initialized_device(devp))){
 	    goto found;
 	}
     return NULL;
@@ -688,7 +688,7 @@ static bool allocation_filter(struct gps_device_t *device, gnss_type type)
      * If we don't, open it and sniff packets until we do. 
      */
     if (allocated_device(device) && !initialized_device(device)) {
-	if (open_device(device->gpsdata.gps_device) == NULL) {
+	if (open_device(device->gpsdata.dev.path) == NULL) {
 	    free_device(device);
 	    return false;
 	}
@@ -697,7 +697,7 @@ static bool allocation_filter(struct gps_device_t *device, gnss_type type)
     gpsd_report(LOG_PROG, 
 		"user requires %d=%s, device %d=%s emits packet type %d, observed mask is 0x%0x, checking against 0x%0x\n", 
 		type, classmap[type].name,
-		(int)(device - devices), device->gpsdata.gps_device,
+		(int)(device - devices), device->gpsdata.dev.path,
 		device->packet.type,
 		device->observed,
 		classmap[type].typemask);
@@ -799,7 +799,7 @@ static struct channel_t *assign_channel(struct subscriber_t *user,
 		    sub_index(user), 
 		    (int)(channel->device - devices),
 		    channel->device->gpsdata.gps_fd,
-		    channel->device->gpsdata.gps_device);
+		    channel->device->gpsdata.dev.path);
     else {
 	if (gpsd_activate(channel->device, true) < 0) {
 
@@ -821,8 +821,8 @@ static struct channel_t *assign_channel(struct subscriber_t *user,
 		/*@ -sefparams @*/
 		throttled_write(user, "GPSD,F=", 7);
 		throttled_write(user,
-				channel->device->gpsdata.gps_device,
-				strlen(channel->device->gpsdata.gps_device));
+				channel->device->gpsdata.dev.path,
+				strlen(channel->device->gpsdata.dev.path));
 		throttled_write(user, "\r\n", 2);
 		/*@ +sefparams @*/
 	    }
@@ -842,7 +842,7 @@ static struct channel_t *assign_channel(struct subscriber_t *user,
 #ifdef GPSDNG_ENABLE
 	if (newstyle(user) && was_unassigned)
 	    (void)snprintf(buf, sizeof(buf), "{\"class\":\"DEVICE\",\"device\":\"%s\",\"activated\":%2.2f}\r\n",
-			   channel->device->gpsdata.gps_device,
+			   channel->device->gpsdata.dev.path,
 			   timestamp());
 #endif /* GPSDNG_ENABLE */
 	/*@ -sefparams +matchanyintegral @*/
@@ -973,8 +973,8 @@ static void set_serial(struct gps_device_t *device,
 		       speed_t speed, char *modestring)
 /* set serial parameters for a device from a speed and modestring */
 {
-    unsigned int stopbits = device->gpsdata.stopbits;
-    char parity = (char)device->gpsdata.parity;
+    unsigned int stopbits = device->gpsdata.dev.stopbits;
+    char parity = (char)device->gpsdata.dev.parity;
     int wordsize = 8;
 
     if (strchr("78", *modestring)!= NULL) {
@@ -1069,15 +1069,15 @@ static bool handle_oldstyle(struct subscriber_t *sub, char *buf,
 	    }
 #endif /* FIXED_PORT_SPEED */
 	    if (channel->device) {
-		if ( channel->device->gpsdata.parity == 0 ) {
+		if ( channel->device->gpsdata.dev.parity == 0 ) {
 			/* zero parity breaks the next snprintf */
-			channel->device->gpsdata.parity = (unsigned)'N';
+			channel->device->gpsdata.dev.parity = (unsigned)'N';
 		}
 		(void)snprintf(phrase, sizeof(phrase), ",B=%d %u %c %u",
 		    (int)gpsd_get_speed(&channel->device->ttyset),
-			9 - channel->device->gpsdata.stopbits,
-			(int)channel->device->gpsdata.parity,
-			channel->device->gpsdata.stopbits);
+			9 - channel->device->gpsdata.dev.stopbits,
+			(int)channel->device->gpsdata.dev.parity,
+			channel->device->gpsdata.dev.stopbits);
 	    } else {
 		(void)strlcpy(phrase, ",B=?", sizeof(phrase));
 	    }
@@ -1091,14 +1091,14 @@ static bool handle_oldstyle(struct subscriber_t *sub, char *buf,
 		    double cycle = strtod(++p, &p);
 		    if (dev->rate_switcher != NULL && cycle >= dev->min_cycle)
 			if (dev->rate_switcher(channel->device, cycle))
-			    channel->device->gpsdata.cycle = cycle;
+			    channel->device->gpsdata.dev.cycle = cycle;
 		}
 		if (dev->rate_switcher == NULL)
 		    (void)snprintf(phrase, sizeof(phrase),
-				   ",C=%.2f", channel->device->gpsdata.cycle);
+				   ",C=%.2f", channel->device->gpsdata.dev.cycle);
 		else
 		    (void)snprintf(phrase, sizeof(phrase), ",C=%.2f %.2f",
-				   channel->device->gpsdata.cycle, channel->device->gpsdata.mincycle);
+				   channel->device->gpsdata.dev.cycle, channel->device->gpsdata.dev.mincycle);
 	    }
 	    break;
 #endif /* ALLOW_RECONFIGURE */
@@ -1160,7 +1160,7 @@ static bool handle_oldstyle(struct subscriber_t *sub, char *buf,
 	    /*@ +branchstate @*/
 	    if (channel != NULL && channel->device != NULL)
 		(void)snprintf(phrase, sizeof(phrase), ",F=%s",
-			 channel->device->gpsdata.gps_device);
+			 channel->device->gpsdata.dev.path);
 	    else
 		(void)strlcpy(phrase, ",F=?", sizeof(phrase));
 	    break;
@@ -1211,8 +1211,8 @@ static bool handle_oldstyle(struct subscriber_t *sub, char *buf,
 		    j++;
 	    (void)snprintf(phrase, sizeof(phrase), ",K=%d ", j);
 	    for (i = 0; i < MAXDEVICES; i++) {
-		if (allocated_device(&devices[i]) && strlen(phrase)+strlen(devices[i].gpsdata.gps_device)+1 < sizeof(phrase)) {
-		    (void)strlcat(phrase, devices[i].gpsdata.gps_device, sizeof(phrase));
+		if (allocated_device(&devices[i]) && strlen(phrase)+strlen(devices[i].gpsdata.dev.path)+1 < sizeof(phrase)) {
+		    (void)strlcat(phrase, devices[i].gpsdata.dev.path, sizeof(phrase));
 		    (void)strlcat(phrase, " ", sizeof(phrase));
 		}
 	    }
@@ -1247,7 +1247,7 @@ static bool handle_oldstyle(struct subscriber_t *sub, char *buf,
 	    if (!channel || !channel->device)
 		(void)snprintf(phrase, sizeof(phrase), ",N=?");
 	    else
-		(void)snprintf(phrase, sizeof(phrase), ",N=%u", channel->device->gpsdata.driver_mode);
+		(void)snprintf(phrase, sizeof(phrase), ",N=%u", channel->device->gpsdata.dev.driver_mode);
 	    break;
 	case 'O':
 	    if ((channel=mandatory_assign_channel(sub, GPS, NULL))== NULL || !have_fix(channel))
@@ -1564,7 +1564,7 @@ static void json_devicelist_dump(char *reply, size_t replylen)
     (void)strlcpy(reply, 
 		  "{\"class\"=\"DEVICES\",\"devices\":[", replylen);
     for (devp = devices; devp < devices + MAXDEVICES; devp++)
-	if (allocated_device(devp) && strlen(reply)+strlen(devp->gpsdata.gps_device)+3 < replylen-1) {
+	if (allocated_device(devp) && strlen(reply)+strlen(devp->gpsdata.dev.path)+3 < replylen-1) {
 	    json_device_dump(devp,
 			     reply+strlen(reply), replylen-strlen(reply));
 	    (void)strlcat(reply, ",", replylen);
@@ -1678,7 +1678,7 @@ static void handle_newstyle_request(struct subscriber_t *sub,
 		    for (chp = channels; chp < channels + NITEMS(channels); chp++)
 			if (chp->subscriber != sub)
 			    continue;
-			else if (devconf.device[0] != '\0' && chp->device && strcmp(chp->device->gpsdata.gps_device, devconf.device)!=0)
+			else if (devconf.device[0] != '\0' && chp->device && strcmp(chp->device->gpsdata.dev.path, devconf.device)!=0)
 			    continue;
 			else {
 			    channel = chp;
@@ -1689,7 +1689,7 @@ static void handle_newstyle_request(struct subscriber_t *sub,
 				       "{\"class\":ERROR\",\"message\":\"Multiple subscribers, cannot change control bits.\"}\r\n");
 		    else {
 			/* now that channel is selected, apply changes */
-			if (devconf.native != channel->device->gpsdata.driver_mode)
+			if (devconf.native != channel->device->gpsdata.dev.driver_mode)
 			    channel->device->device_type->mode_switcher(channel->device, devconf.native);
 			set_serial(channel->device, 
 				   (speed_t)devconf.bps, devconf.serialmode);
@@ -1701,7 +1701,7 @@ static void handle_newstyle_request(struct subscriber_t *sub,
 	    for (chp = channels; chp < channels + NITEMS(channels); chp++)
 		if (chp->subscriber != sub)
 		    continue;
-		else if (devconf.device[0] != '\0' && chp->device && strcmp(chp->device->gpsdata.gps_device, devconf.device)!=0)
+		else if (devconf.device[0] != '\0' && chp->device && strcmp(chp->device->gpsdata.dev.path, devconf.device)!=0)
 		    continue;
 		else {
 		    json_configdev_dump(chp->device, 
@@ -2151,7 +2151,7 @@ int main(int argc, char *argv[])
 			    char id2[NMEA_MAX];
 			    (void)snprintf(id2, sizeof(id2), 
 					   "{\"class\":\"DEVICE\",\"name\":\"%s\",\"subtype\":\"%s\"}",
-					   device->gpsdata.gps_device,
+					   device->gpsdata.dev.path,
 					   device->subtype);
 			    (void)strlcat(id2, "\r\n", sizeof(id2));
 			    notify_watchers(device, WATCH_NEWSTYLE, id2);
diff --git a/gpsd_json.c b/gpsd_json.c
index b95e8f52..0ed8d0cd 100644
--- a/gpsd_json.c
+++ b/gpsd_json.c
@@ -30,7 +30,7 @@ void json_tpv_dump(struct gps_data_t *gpsdata, struct gps_fix_t *fixp,
     (void)snprintf(reply+strlen(reply),
 		   replylen-strlen(reply),
 		   "\"device\":\"%s\",",
-		   gpsdata->gps_device);
+		   gpsdata->dev.path);
     if (isnan(fixp->time)==0)
 	(void)snprintf(reply+strlen(reply),
 		       replylen-strlen(reply),
@@ -115,7 +115,7 @@ void json_sky_dump(struct gps_data_t *datap, char *reply, size_t replylen)
     (void)snprintf(reply+strlen(reply),
 		   replylen-strlen(reply),
 		   "\"device\":\"%s\",",
-		   datap->gps_device);
+		   datap->dev.path);
     if (isnan(datap->sentence_time)==0)
 	(void)snprintf(reply+strlen(reply),
 		       replylen-strlen(reply),
@@ -161,7 +161,7 @@ void json_device_dump(struct gps_device_t *device,
 {
     struct classmap_t *cmp;
     (void)strlcpy(reply, "{\"class\":\"DEVICE\",\"path\":\"", replylen);
-    (void)strlcat(reply, device->gpsdata.gps_device, replylen);
+    (void)strlcat(reply, device->gpsdata.dev.path, replylen);
     (void)strlcat(reply, "\",", replylen);
     (void)snprintf(reply+strlen(reply), replylen-strlen(reply),
 		   "\"activated\":%2.2f,", device->gpsdata.online);
@@ -249,13 +249,13 @@ void json_configdev_dump(struct gps_device_t *devp, char *reply, size_t replylen
 {
     (void)snprintf(reply, replylen,
 		   "{\"class\":\"CONFIGDEV\",\"device\":\"%s\",\"native\":%d,\"bps\":%d,\"serialmode\":\"%u%c%u\",\"cycle\":%2.2f",
-		   devp->gpsdata.gps_device,
-		   devp->gpsdata.driver_mode,
+		   devp->gpsdata.dev.path,
+		   devp->gpsdata.dev.driver_mode,
 		   (int)gpsd_get_speed(&devp->ttyset),
-		   9 - devp->gpsdata.stopbits,
-		   (int)devp->gpsdata.parity,
-		   devp->gpsdata.stopbits,
-		   devp->gpsdata.cycle);
+		   9 - devp->gpsdata.dev.stopbits,
+		   (int)devp->gpsdata.dev.parity,
+		   devp->gpsdata.dev.stopbits,
+		   devp->gpsdata.dev.cycle);
     if (devp->device_type->rate_switcher != NULL)
 	(void)snprintf(reply+strlen(reply), replylen-strlen(reply),
 		       ",\"mincycle\":%2.2f",
diff --git a/gpsmon.c b/gpsmon.c
index 80dc3ae5..25293fdb 100644
--- a/gpsmon.c
+++ b/gpsmon.c
@@ -227,7 +227,7 @@ bool monitor_control_send(/*@in@*/unsigned char *buf, size_t len)
 	if (!serial) {
 	    /*@ -sefparams @*/
 	    assert(write(controlfd, "!", 1) != -1);
-	    assert(write(controlfd, session.gpsdata.gps_device, strlen(session.gpsdata.gps_device)) != -1);
+	    assert(write(controlfd, session.gpsdata.dev.path, strlen(session.gpsdata.dev.path)) != -1);
 	    assert(write(controlfd, "=", 1) != -1);
 	    /*@ +sefparams @*/
 	    /*
@@ -263,8 +263,8 @@ static bool monitor_raw_send(/*@in@*/unsigned char *buf, size_t len)
 	if (!serial) {
 	    /*@ -sefparams @*/
 	    assert(write(controlfd, "!", 1) != -1);
-	    assert(write(controlfd, session.gpsdata.gps_device,
-			 strlen(session.gpsdata.gps_device)) != -1);
+	    assert(write(controlfd, session.gpsdata.dev.path,
+			 strlen(session.gpsdata.dev.path)) != -1);
 	    assert(write(controlfd, "=", 1) != -1);
 	    /*@ +sefparams @*/
 	}
@@ -512,16 +512,16 @@ int main (int argc, char **argv)
 	else
 	    command((char *)buf, sizeof(buf), "O\r\n");	/* force device allocation */
 	command((char *)buf, sizeof(buf), "F\r\n");
-	(void)strlcpy(session.gpsdata.gps_device, (char *)buf+7, PATH_MAX);
+	(void)strlcpy(session.gpsdata.dev.path, (char *)buf+7, PATH_MAX);
 	command((char *)buf, sizeof(buf), "R=2\r\n");
 	/*@ +compdef @*/
 	serial = false;
     } else {
-	(void)strlcpy(session.gpsdata.gps_device, argv[optind], PATH_MAX);
+	(void)strlcpy(session.gpsdata.dev.path, argv[optind], PATH_MAX);
 	if (gpsd_activate(&session, false) == -1) {
 	    gpsd_report(LOG_ERROR,
 			  "activation of device %s failed, errno=%d\n",
-			  session.gpsdata.gps_device, errno);
+			  session.gpsdata.dev.path, errno);
 	    exit(2);
 	}
 
@@ -577,14 +577,14 @@ int main (int argc, char **argv)
 	(void)wattrset(statwin, A_BOLD);
 	if (serial)
 	    display(statwin, 0, 0, "%s %4d %c %d",
-		    session.gpsdata.gps_device,
+		    session.gpsdata.dev.path,
 		    gpsd_get_speed(&session.ttyset),
-		    session.gpsdata.parity,
-		    session.gpsdata.stopbits);
+		    session.gpsdata.dev.parity,
+		    session.gpsdata.dev.stopbits);
 	else
 	    /*@ -nullpass @*/
 	    display(statwin, 0, 0, "%s:%s:%s",
-		    source.server, source.port, session.gpsdata.gps_device);
+		    source.server, source.port, session.gpsdata.dev.path);
 	    /*@ +nullpass @*/
 	(void)wattrset(statwin, A_NORMAL);
 	(void)wmove(cmdwin, 0,0);
@@ -762,8 +762,8 @@ int main (int argc, char **argv)
 		    monitor_complain("No device defined yet");
 		else if (serial) {
 		    speed_t speed;
-		    char parity = (char)session.gpsdata.parity;
-		    unsigned int stopbits = session.gpsdata.stopbits;
+		    char parity = (char)session.gpsdata.dev.parity;
+		    unsigned int stopbits = session.gpsdata.dev.stopbits;
 		    char *modespec;
 
 		    modespec = strchr(arg, ':');
diff --git a/gpsutils.c b/gpsutils.c
index 24cb29af..8e75e3f6 100644
--- a/gpsutils.c
+++ b/gpsutils.c
@@ -547,7 +547,7 @@ gps_mask_t dop(struct gps_data_t *gpsdata)
     } else {
 	gpsd_report(LOG_INF,
 	    "LOS matrix is singular, can't calculate DOPs - source '%s'\n",
-	    gpsdata->gps_device);
+	    gpsdata->dev.path);
 	return 0;
     }
 
diff --git a/libgps.c b/libgps.c
index f74f6dfc..0418bfc9 100644
--- a/libgps.c
+++ b/libgps.c
@@ -52,11 +52,6 @@ int gps_close(struct gps_data_t *gpsdata)
 /* close a gpsd connection */
 {
     int retval = close(gpsdata->gps_fd);
-    if (gpsdata->gps_id) {
-	(void)free(gpsdata->gps_id);
-	gpsdata->gps_id = NULL;
-    }
-    gpsdata->gps_device[0] = '\0';
     /*@i@*/(void)free(gpsdata);
     return retval;
 }
@@ -137,19 +132,19 @@ int gps_unpack(char *buf, struct gps_data_t *gpsdata)
 			break;
 		    case 'B':
 			if (sp[2] == '?') {
-			    gpsdata->baudrate = gpsdata->stopbits = 0;
+			    gpsdata->dev.baudrate = gpsdata->dev.stopbits = 0;
 			} else
 			    (void)sscanf(sp, "B=%u %*d %*s %u",
-				   &gpsdata->baudrate, &gpsdata->stopbits);
+				   &gpsdata->dev.baudrate, &gpsdata->dev.stopbits);
 			break;
 		    case 'C':
 			if (sp[2] == '?')
-			    gpsdata->mincycle = gpsdata->cycle = 0;
+			    gpsdata->dev.mincycle = gpsdata->dev.cycle = 0;
 			else {
 			    if (sscanf(sp, "C=%lf %lf",
-					 &gpsdata->cycle,
-				       &gpsdata->mincycle) < 2)
-				gpsdata->mincycle = gpsdata->cycle;
+					 &gpsdata->dev.cycle,
+				       &gpsdata->dev.mincycle) < 2)
+				gpsdata->dev.mincycle = gpsdata->dev.cycle;
 			}
 			break;
 		    case 'D':
@@ -175,13 +170,12 @@ int gps_unpack(char *buf, struct gps_data_t *gpsdata)
 #undef DEFAULT
 			}
 			break;
-		    case 'F':
-			/*@ -mustfreeonly */
+		    case 'F': /*@ -mustfreeonly */
 			if (sp[2] == '?')
-			    gpsdata->gps_device[0] = '\0';
+			    gpsdata->dev.path[0] = '\0';
 			else {
 			    /*@ -mayaliasunique @*/
-			    strncpy(gpsdata->gps_device, sp+2, PATH_MAX);
+			    strncpy(gpsdata->dev.path, sp+2, PATH_MAX);
 			    /*@ +mayaliasunique @*/
 			    gpsdata->set |= DEVICE_SET;
 			}
@@ -189,12 +183,10 @@ int gps_unpack(char *buf, struct gps_data_t *gpsdata)
 			break;
 		    case 'I':
 			/*@ -mustfreeonly */
-			if (gpsdata->gps_id)
-			    free(gpsdata->gps_id);
 			if (sp[2] == '?')
-			    gpsdata->gps_id = NULL;
+			    gpsdata->dev.subtype[0] = '\0';
 			else {
-			    gpsdata->gps_id = strdup(sp+2);
+			    (void)strlcpy(gpsdata->dev.subtype, sp+2, sizeof(gpsdata->dev.subtype));
 			    gpsdata->set |= DEVICEID_SET;
 			}
 			/*@ +mustfreeonly */
@@ -229,9 +221,9 @@ int gps_unpack(char *buf, struct gps_data_t *gpsdata)
 			break;
 		    case 'N':
 			if (sp[2] == '?')
-			    gpsdata->driver_mode = MODE_NMEA;
+			    gpsdata->dev.driver_mode = MODE_NMEA;
 			else
-			    gpsdata->driver_mode = (unsigned)atoi(sp+2);
+			    gpsdata->dev.driver_mode = (unsigned)atoi(sp+2);
 			break;
 		    case 'O':
 			if (sp[2] == '?') {
@@ -616,9 +608,9 @@ static void data_dump(struct gps_data_t *collect, time_t now)
 	}
     }
     if (collect->set & DEVICE_SET)
-	printf("Device is %s\n", collect->gps_device);
+	printf("Device is %s\n", collect->dev.path);
     if (collect->set & DEVICEID_SET)
-	printf("GPSD ID is %s\n", collect->gps_id);
+	printf("GPSD ID is %s\n", collect->dev.subtype);
     if (collect->set & DEVICELIST_SET) {
 	int i;
 	printf("%d devices:\n", collect->devices.ndevices);
diff --git a/libgps_json.c b/libgps_json.c
index b6960ce0..ec5b76ed 100644
--- a/libgps_json.c
+++ b/libgps_json.c
@@ -25,8 +25,8 @@ static int json_tpv_read(const char *buf,
     int status;
     const struct json_attr_t json_attrs_1[] = {
 	{"class",  check,   .dflt.check = "TPV"},
-	{"device", string,  .addr.string.ptr = gpsdata->gps_device,
-			    .addr.string.len = sizeof(gpsdata->gps_device)},
+	{"device", string,  .addr.string.ptr = gpsdata->dev.path,
+			    .addr.string.len = sizeof(gpsdata->dev.path)},
 	{"tag",    string,  .addr.string.ptr = gpsdata->tag,
 			    .addr.string.len = sizeof(gpsdata->tag)},
 	{"time",   real,    .addr.real = &gpsdata->fix.time,
@@ -111,7 +111,7 @@ static int json_sky_read(const char *buf,
     };
     const struct json_attr_t json_attrs_2[] = {
 	{"class",      check,   .dflt.check = "SKY"},
-	{"device",     string,  .addr.string.ptr  = gpsdata->gps_device,
+	{"device",     string,  .addr.string.ptr  = gpsdata->dev.path,
 				.addr.string.len = PATH_MAX},
 	{"tag",	       string,  .addr.string.ptr  = gpsdata->tag,
 				.addr.string.len = MAXTAGLEN},
@@ -146,7 +146,8 @@ static int json_device_read(const char *buf,
 {
     const struct json_attr_t json_attrs_device[] = {
 	{"class",      check,      .dflt.check = "DEVICE"},
-	{"path",       string,     .addr.string.ptr  = dev->path,
+	
+        {"path",       string,     .addr.string.ptr  = dev->path,
 	                           .addr.string.len = sizeof(dev->path)},
 	{"activated",  real,       .addr.real = &dev->activated},
 	{"flags",      integer,    .addr.integer = &dev->flags},
diff --git a/libgpsd_core.c b/libgpsd_core.c
index eb3788bf..7050a6ae 100644
--- a/libgpsd_core.c
+++ b/libgpsd_core.c
@@ -47,7 +47,7 @@ int gpsd_switch_driver(struct gps_device_t *session, char* type_name)
 	    gpsd_report(LOG_PROG, "selecting %s driver...\n", (*dp)->type_name);
 	    gpsd_assert_sync(session);
 	    /*@i@*/session->device_type = *dp;
-	    session->gpsdata.mincycle = session->device_type->min_cycle;
+	    session->gpsdata.dev.mincycle = session->device_type->min_cycle;
 	    if (!session->context->readonly && session->device_type->probe_subtype != NULL)
 		session->device_type->probe_subtype(session, session->packet.counter = 0);
 #ifdef ALLOW_RECONFIGURE
@@ -70,7 +70,7 @@ void gpsd_init(struct gps_device_t *session, struct gps_context_t *context, char
 {
     /*@ -mayaliasunique @*/
     if (device != NULL)
-	(void)strlcpy(session->gpsdata.gps_device, device, PATH_MAX);
+	(void)strlcpy(session->gpsdata.dev.path, device, sizeof(session->gpsdata.dev.path));
     /*@ -mustfreeonly @*/
     session->device_type = NULL;	/* start by hunting packets */
     session->observed = 0;
@@ -89,7 +89,7 @@ void gpsd_init(struct gps_device_t *session, struct gps_context_t *context, char
     session->gpsdata.gdop = NAN;
     session->gpsdata.epe = NAN;
     session->mag_var = NAN;
-    session->gpsdata.cycle = session->gpsdata.mincycle = 1; 
+    session->gpsdata.dev.cycle = session->gpsdata.dev.mincycle = 1; 
 
     /* tty-level initialization */
     gpsd_tty_init(session);
@@ -127,7 +127,7 @@ void gpsd_deactivate(struct gps_device_t *session)
     }
 #endif /* ALLOW_RECONFIGURE */
     gpsd_report(LOG_INF, "closing GPS=%s (%d)\n",
-		session->gpsdata.gps_device, session->gpsdata.gps_fd);
+		session->gpsdata.dev.path, session->gpsdata.gps_fd);
     (void)gpsd_close(session);
 }
 
@@ -164,7 +164,7 @@ static /*@null@*/void *gpsd_ppsmonitor(void *arg)
 	} else {
 	    gpsd_report(LOG_RAW, "pps-detect (%s) on %s changed to %d\n",
 			((pps_device==TIOCM_CAR) ? "DCD" : "CTS"),
-			  session->gpsdata.gps_device, state);
+			  session->gpsdata.dev.path, state);
 	    laststate = state;
 	    unchanged = 0;
 	}
@@ -703,7 +703,7 @@ gps_mask_t gpsd_poll(struct gps_device_t *session)
 	session->gpsdata.d_xmit_time = timestamp();
 	gpsd_report(LOG_RAW,
 		    "packet sniff on %s finds type %d\n",
-		    session->gpsdata.gps_device,
+		    session->gpsdata.dev.path,
 		    session->packet.type);
 	if (session->packet.type > COMMENT_PACKET) {
 	    session->observed |= PACKET_TYPEMASK(session->packet.type);
@@ -721,15 +721,14 @@ gps_mask_t gpsd_poll(struct gps_device_t *session)
     gpsd_report(LOG_RAW+2, "GPS sent %zd new characters\n", newlen);
     if (newlen == -1)	{		/* read error */
 	gpsd_report(LOG_INF, "GPS on %s is offline (%lf sec since data)\n",
-		    session->gpsdata.gps_device,
+		    session->gpsdata.dev.path,
 		    timestamp() - session->gpsdata.online);
 	session->gpsdata.online = 0;
 	return 0;
     } else if (newlen == 0) {		/* no new data */
-	if (session->device_type != NULL && timestamp()>session->gpsdata.online+session->gpsdata.
-cycle+1){
+	if (session->device_type != NULL && timestamp()>session->gpsdata.online+session->gpsdata.dev.cycle+1){
 	gpsd_report(LOG_INF, "GPS on %s is offline (%lf sec since data)\n",
-		    session->gpsdata.gps_device,
+		    session->gpsdata.dev.path,
 		    timestamp() - session->gpsdata.online);
 	session->gpsdata.online = 0;
 	    return 0;
@@ -737,14 +736,14 @@ cycle+1){
 	    return ONLINE_SET;
     } else if (session->packet.outbuflen == 0) {   /* got new data, but no packet */
 	gpsd_report(LOG_RAW+3, "New data on %s, not yet a packet\n",
-			    session->gpsdata.gps_device);
+			    session->gpsdata.dev.path);
 	return ONLINE_SET;
     } else {
 	gps_mask_t received, dopmask = 0;
 	session->gpsdata.online = timestamp();
 
 	gpsd_report(LOG_RAW+3, "Accepted packet on %s.\n",
-			    session->gpsdata.gps_device);
+			    session->gpsdata.dev.path);
 	/*@ -nullstate @*/
 	if (session->gpsdata.raw_hook)
 	    session->gpsdata.raw_hook(&session->gpsdata,
@@ -821,7 +820,7 @@ cycle+1){
 #endif /* BINARY_ENABLE */
 	    if (buf2[0] != '\0') {
 		gpsd_report(LOG_IO, "<= GPS (binary) %s: %s",
-			    session->gpsdata.gps_device, buf2);
+			    session->gpsdata.dev.path, buf2);
 		if (session->gpsdata.raw_hook)
 		    session->gpsdata.raw_hook(&session->gpsdata,
 					      buf2, strlen(buf2), 1);
diff --git a/serial.c b/serial.c
index 96fa95bc..b99198ed 100644
--- a/serial.c
+++ b/serial.c
@@ -104,7 +104,7 @@ void gpsd_set_speed(struct gps_device_t *session,
     else
       rate =  B115200;
 
-    if (rate!=cfgetispeed(&session->ttyset) || (unsigned int)parity!=session->gpsdata.parity || stopbits!=session->gpsdata.stopbits) {
+    if (rate!=cfgetispeed(&session->ttyset) || (unsigned int)parity!=session->gpsdata.dev.parity || stopbits!=session->gpsdata.dev.stopbits) {
 
 	/* 
 	 * Don't mess with this conditional! Speed zero is supposed to mean
@@ -191,9 +191,9 @@ void gpsd_set_speed(struct gps_device_t *session,
     gpsd_report(LOG_INF, "speed %d, %d%c%d\n", 
 		gpsd_get_speed(&session->ttyset), 9-stopbits, parity, stopbits);
 
-    session->gpsdata.baudrate = (unsigned int)speed;
-    session->gpsdata.parity = (unsigned int)parity;
-    session->gpsdata.stopbits = stopbits;
+    session->gpsdata.dev.baudrate = (unsigned int)speed;
+    session->gpsdata.dev.parity = (unsigned int)parity;
+    session->gpsdata.dev.stopbits = stopbits;
 
     if (!session->context->readonly) {
 	/*
@@ -224,24 +224,24 @@ int gpsd_open(struct gps_device_t *session)
     if (session->context->netgnss_service == netgnss_remotegpsd){
 	session->gpsdata.gps_fd = session->context->dsock;
 	session->saved_baud = 57600;
-	session->gpsdata.baudrate = 57600;
-	session->gpsdata.parity = 'N';
-	session->gpsdata.stopbits = 1;
+	session->gpsdata.dev.baudrate = 57600;
+	session->gpsdata.dev.parity = 'N';
+	session->gpsdata.dev.stopbits = 1;
 	session->context->readonly = 1;
 	return session->gpsdata.gps_fd;
     }
     /*@ -boolops -type @*/
-    if (session->context->readonly || ((stat(session->gpsdata.gps_device, &sb) != -1) && ((sb.st_mode & S_IFCHR) != S_IFCHR))){
+    if (session->context->readonly || ((stat(session->gpsdata.dev.path, &sb) != -1) && ((sb.st_mode & S_IFCHR) != S_IFCHR))){
 	mode = (mode_t)O_RDONLY;
-	gpsd_report(LOG_INF, "opening read-only GPS data source at '%s'\n", session->gpsdata.gps_device);
+	gpsd_report(LOG_INF, "opening read-only GPS data source at '%s'\n", session->gpsdata.dev.path);
     } else {
-	gpsd_report(LOG_INF, "opening GPS data source at '%s'\n", session->gpsdata.gps_device);
+	gpsd_report(LOG_INF, "opening GPS data source at '%s'\n", session->gpsdata.dev.path);
     }
     /*@ +boolops +type @*/
 
-    if ((session->gpsdata.gps_fd = open(session->gpsdata.gps_device, (int)(mode|O_NONBLOCK|O_NOCTTY))) == -1) {
+    if ((session->gpsdata.gps_fd = open(session->gpsdata.dev.path, (int)(mode|O_NONBLOCK|O_NOCTTY))) == -1) {
 	gpsd_report(LOG_ERROR, "device open failed: %s - retrying read-only\n", strerror(errno));
-	if ((session->gpsdata.gps_fd = open(session->gpsdata.gps_device, O_RDONLY|O_NONBLOCK|O_NOCTTY)) == -1) {
+	if ((session->gpsdata.gps_fd = open(session->gpsdata.dev.path, O_RDONLY|O_NONBLOCK|O_NOCTTY)) == -1) {
 	    gpsd_report(LOG_ERROR, "read-only device open failed: %s\n", strerror(errno));
 	    return -1;
 	}
@@ -329,13 +329,13 @@ bool gpsd_next_hunt_setting(struct gps_device_t *session)
 	session->packet.retry_counter = 0;
 	if (session->baudindex++ >= (unsigned int)(sizeof(rates)/sizeof(rates[0]))-1) {
 	    session->baudindex = 0;
-	    if (session->gpsdata.stopbits++ >= 2)
+	    if (session->gpsdata.dev.stopbits++ >= 2)
 		return false;			/* hunt is over, no sync */
 	}
 	gpsd_set_speed(session,
 		       rates[session->baudindex],
-		       (unsigned char)session->gpsdata.parity,
-		       session->gpsdata.stopbits);
+		       (unsigned char)session->gpsdata.dev.parity,
+		       session->gpsdata.dev.stopbits);
     }
 
     return true;	/* keep hunting */
diff --git a/www/protocol-transition.txt b/www/protocol-transition.txt
index 4e910bfb..05bc7f32 100644
--- a/www/protocol-transition.txt
+++ b/www/protocol-transition.txt
@@ -256,3 +256,29 @@ protocol.  Do not rely on it.
 
 The old 'Z' and '$' commands, used by the developers for profiling, 
 have no equivalents.  We'll implement them if we need them.
+
+== How the gps_data_t structure has changed == 
+
+The client libary's reporting structure, struct gpsdata_t, has a new
+substructure (struct device_t) named "dev" that groups together
+information about the device that shipped the last update to the
+client.  The members of this structure replace several top-level
+struct gpsdata members in older versions.
+
+Most notably, the gps_device member has been replaced by dev.path.
+It is valid after every response with a device tag (DEVICE, TPV, SKY,
+AIS, RTCM2, RTCM3, CONFIGDEV).
+
+The top-level gps_id member is replaced by dev.subtype.  This data
+should be considered valid only when DEVICEID_SET is on in the
+top-level set member.
+
+The dev members baudrate, parity, stopbits, cycle, mincycle, and
+driver_mode replace older top-level members.  They should be
+considered valid only when DEVICE_SET is on in the top-level set
+member (note: this flag is not reliably set yet, work in progress).
+
+The top-level members ndevices and devicelist (used only on the client
+side) have been replaced by an array of struct device_t structures.
+Storage for pathnames is no longer dynamically allocated, but rather
+lives in a union with several other substructures.
diff --git a/xgps.c b/xgps.c
index 98ff109b..9c5a3f59 100644
--- a/xgps.c
+++ b/xgps.c
@@ -969,7 +969,7 @@ update_panel(struct gps_data_t *gpsdata, char *message,
 		XmTextFieldSetString(text_9, "n/a");
 	if (gpsdata->set & DEVICEID_SET) {
 		(void)strlcpy(s, "xgps: ", sizeof(s));
-		(void)strlcpy(s+6, gpsdata->gps_id, sizeof(s)-6);
+		(void)strlcpy(s+6, gpsdata->dev.subtype, sizeof(s)-6);
 		set_title(s);
 	}
 	if (gpsdata->online == 0) {