Contain the assumption that time hinting is done to NTPD.

Because it might be going to chrony. Or something else.

No logic changes, just name changes and one new derived #define,
TIMEHINT_ENABLE.

21 files changed, 175 insertions, 161 deletions

diff --git a/driver_evermore.c b/driver_evermore.c
index 50b4823f..092da3a1 100644
--- a/driver_evermore.c
+++ b/driver_evermore.c
@@ -633,9 +633,9 @@ const struct gps_type_t evermore_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = evermore_control_send,	/* how to send a control string */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* defined(EVERMORE_ENABLE) && defined(BINARY_ENABLE) */
diff --git a/driver_garmin.c b/driver_garmin.c
index 32015573..ea33320b 100644
--- a/driver_garmin.c
+++ b/driver_garmin.c
@@ -1224,8 +1224,8 @@ static ssize_t garmin_control_send(struct gps_device_t *session,
 }
 #endif /* CONTROLSEND_ENABLE */
 
-#ifdef NTPSHM_ENABLE
-static double garmin_ntp_offset(struct gps_device_t *session)
+#ifdef TIMEHINT_ENABLE
+static double garmin_time_offset(struct gps_device_t *session)
 {
     if (session->sourcetype == source_usb) {
 	return 0.035;		/* Garmin USB, expect +/- 40mS jitter */
@@ -1244,7 +1244,7 @@ static double garmin_ntp_offset(struct gps_device_t *session)
     }
     return 0.430;		/* WTF?  WAG */
 }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
 
 /* this is everything we export */
 #ifdef __UNUSED__
@@ -1391,9 +1391,9 @@ const struct gps_type_t garmin_usb_binary_old =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = garmin_control_send,	/* send raw bytes */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = garmin_ntp_offset,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = garmin_time_offset,
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* __UNUSED__ */
@@ -1420,9 +1420,9 @@ const struct gps_type_t garmin_usb_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = garmin_control_send,	/* send raw bytes */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = garmin_ntp_offset,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = garmin_time_offset,
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 
@@ -1448,9 +1448,9 @@ const struct gps_type_t garmin_ser_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = garmin_control_send,	/* send raw bytes */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = garmin_ntp_offset,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = garmin_time_offset,
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 
diff --git a/driver_geostar.c b/driver_geostar.c
index d819e4ad..7830eaad 100644
--- a/driver_geostar.c
+++ b/driver_geostar.c
@@ -599,12 +599,12 @@ static void geostar_mode(struct gps_device_t *session, int mode)
 }
 #endif /* RECONFIGURE_ENABLE */
 
-#ifdef NTPSHM_ENABLE
-static double geostar_ntp_offset(struct gps_device_t *session UNUSED)
+#ifdef TIMEHINT_ENABLE
+static double geostar_time_offset(struct gps_device_t *session UNUSED)
 {
     return 0.31;
 }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
 
 /* this is everything we export */
 /* *INDENT-OFF* */
@@ -629,9 +629,9 @@ const struct gps_type_t geostar_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = geostar_control_send,/* how to send commands */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = geostar_ntp_offset,
-#endif /* NTPSHM_ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = geostar_time_offset,
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 
diff --git a/driver_italk.c b/driver_italk.c
index 2521351f..cdb3c7b9 100644
--- a/driver_italk.c
+++ b/driver_italk.c
@@ -418,9 +418,9 @@ const struct gps_type_t italk_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = NULL,		/* no control string sender */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* defined(ITRAX_ENABLE) && defined(BINARY_ENABLE) */
diff --git a/driver_navcom.c b/driver_navcom.c
index 5c6fbd24..d67acde9 100644
--- a/driver_navcom.c
+++ b/driver_navcom.c
@@ -1296,9 +1296,9 @@ const struct gps_type_t navcom_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = navcom_control_send,	/* how to send a control string */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 
diff --git a/driver_nmea2000.c b/driver_nmea2000.c
index 42b00f5b..621fb615 100644
--- a/driver_nmea2000.c
+++ b/driver_nmea2000.c
@@ -1617,9 +1617,9 @@ const struct gps_type_t nmea2000 = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = NULL,		/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 
diff --git a/driver_oncore.c b/driver_oncore.c
index 0152933a..45929451 100644
--- a/driver_oncore.c
+++ b/driver_oncore.c
@@ -454,8 +454,8 @@ static void oncore_event_hook(struct gps_device_t *session, event_t event)
     }
 }
 
-#ifdef NTPSHM_ENABLE
-static double oncore_ntp_offset(struct gps_device_t *session UNUSED)
+#ifdef TIMEHINT_ENABLE
+static double oncore_time_offset(struct gps_device_t *session UNUSED)
 {
     /*
      * Only one sentence (NAVSOL) ships time.  0.175 seems best at
@@ -464,7 +464,7 @@ static double oncore_ntp_offset(struct gps_device_t *session UNUSED)
      */
     return 0.175;
 }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
 
 static gps_mask_t oncore_parse_input(struct gps_device_t *session)
 {
@@ -503,9 +503,9 @@ const struct gps_type_t oncore_binary = {
     /* Control string sender - should provide checksum and headers/trailer */
     .control_send   = oncore_control_send,	/* to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset = oncore_ntp_offset,		/* NTP offset array */
-#endif /* NTPSHM_ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset = oncore_time_offset,		/* NTP offset array */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* defined(ONCORE_ENABLE) && defined(BINARY_ENABLE) */
diff --git a/driver_proto.c b/driver_proto.c
index f9f7f060..17413e80 100644
--- a/driver_proto.c
+++ b/driver_proto.c
@@ -453,8 +453,8 @@ static void _proto__set_mode(struct gps_device_t *session, int mode)
 }
 #endif /* RECONFIGURE_ENABLE */
 
-#ifdef NTPSHM_ENABLE
-static double _proto_ntp_offset(struct gps_device_t *session)
+#ifdef TIMEHINT_ENABLE
+static double _proto_time_offset(struct gps_device_t *session)
 {
     /*
      * If NTP notification is enabled, the GPS will occasionally NTP
@@ -468,7 +468,7 @@ static double _proto_ntp_offset(struct gps_device_t *session)
      */
     return MAGIC_CONSTANT;
 }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
 
 static void _proto__wrapup(struct gps_device_t *session)
 {
@@ -525,9 +525,9 @@ const struct gps_type_t _proto__binary = {
     /* Control string sender - should provide checksum and headers/trailer */
     .control_send   = _proto__control_send,
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = _proto_ntp_offset,
-#endif /* NTPSHM_ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = _proto_time_offset,
+#endif /* TIMEHINT_ENABLE */
 /* *INDENT-ON* */
 };
 #endif /* defined(_PROTO__ENABLE) && defined(BINARY_ENABLE) */
diff --git a/driver_sirf.c b/driver_sirf.c
index 48902343..646ae94f 100644
--- a/driver_sirf.c
+++ b/driver_sirf.c
@@ -486,9 +486,9 @@ static gps_mask_t sirf_msg_swversion(struct gps_device_t *session,
     gpsd_report(session->context->debug, LOG_PROG,
 		"SiRF: fv: %0.2f, Driver state flags are: %0x\n",
 		fv, session->driver.sirf.driverstate);
-#ifdef NTPSHM_ENABLE
+#ifdef TIMEHINT_ENABLE
     session->driver.sirf.time_seen = 0;
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
     gpsd_report(session->context->debug, LOG_DATA,
 		"SiRF: FV MID 0x06: subtype='%s' mask={DEVICEID}\n",
 		session->subtype);
@@ -577,7 +577,7 @@ static gps_mask_t sirf_msg_svinfo(struct gps_device_t *session,
 		&& session->driver.sirf.dgps_source == SIRF_DGPS_SOURCE_SBAS)
 	    session->gpsdata.used[session->gpsdata.satellites_used++] = prn;
     }
-#ifdef NTPSHM_ENABLE
+#ifdef TIMEHINT_ENABLE
     if (st < 3) {
 	gpsd_report(session->context->debug, LOG_PROG,
 		    "SiRF: NTPD not enough satellites seen: %d\n", st);
@@ -589,15 +589,15 @@ static gps_mask_t sirf_msg_svinfo(struct gps_device_t *session,
 		    session->gpsdata.skyview_time,
 		    session->context->leap_seconds);
     }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
     gpsd_report(session->context->debug, LOG_DATA,
 		"SiRF: MTD 0x04: visible=%d mask={SATELLITE}\n",
 		session->gpsdata.satellites_visible);
     return SATELLITE_SET;
 }
 
-#ifdef NTPSHM_ENABLE
-static double sirf_ntp_offset(struct gps_device_t *session)
+#ifdef TIMEHINT_ENABLE
+static double sirf_time_offset(struct gps_device_t *session)
 /* return NTP time-offset fudge factor for this device */
 {
     double retval = NAN;
@@ -650,7 +650,7 @@ static double sirf_ntp_offset(struct gps_device_t *session)
 
     return retval;
 }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
 
 static gps_mask_t sirf_msg_navsol(struct gps_device_t *session,
 				  unsigned char *buf, size_t len)
@@ -695,7 +695,7 @@ static gps_mask_t sirf_msg_navsol(struct gps_device_t *session,
     /* byte 21 is "mode 2", not clear how to interpret that */
     session->newdata.time = gpsd_gpstime_resolve(session,
 	(unsigned short)getbes16(buf, 22), (double)getbeu32(buf, 24) * 1e-2);
-#ifdef NTPSHM_ENABLE
+#ifdef TIMEHINT_ENABLE
     if (session->newdata.mode <= MODE_NO_FIX) {
 	gpsd_report(session->context->debug, LOG_PROG,
 		    "SiRF: NTPD no fix, mode: %d\n",
@@ -706,7 +706,7 @@ static gps_mask_t sirf_msg_navsol(struct gps_device_t *session,
 		    session->driver.sirf.time_seen,
 		    session->newdata.time, session->context->leap_seconds);
     }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
     /* fix quality data */
     session->gpsdata.dop.hdop = (double)getub(buf, 20) / 5.0;
     mask |=
@@ -846,7 +846,7 @@ static gps_mask_t sirf_msg_geodetic(struct gps_device_t *session,
 	gpsd_report(session->context->debug, LOG_PROG,
 		    "SiRF: GND 0x29 UTC: %lf\n",
 		    session->newdata.time);
-#ifdef NTPSHM_ENABLE
+#ifdef TIMEHINT_ENABLE
 	if (session->newdata.mode <= MODE_NO_FIX) {
 	    gpsd_report(session->context->debug, LOG_PROG,
 			"SiRF: NTPD no fix, mode: $d\n",
@@ -864,7 +864,7 @@ static gps_mask_t sirf_msg_geodetic(struct gps_device_t *session,
 	    mask |= PPSTIME_IS;
 	}
 
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
 	/* skip 4 bytes of satellite map */
 	session->newdata.altitude = getbes32(buf, 35) * 1e-2;
 	/* skip 1 byte of map datum */
@@ -979,7 +979,7 @@ static gps_mask_t sirf_msg_ublox(struct gps_device_t *session,
 	/*@ -compdef */
 	session->newdata.time = (timestamp_t)mkgmtime(&unpacked_date) + subseconds;
 	/*@ +compdef */
-#ifdef NTPSHM_ENABLE
+#ifdef TIMEHINT_ENABLE
 	if (0 == (session->driver.sirf.time_seen & TIME_SEEN_UTC_2)) {
 	    gpsd_report(session->context->debug, LOG_RAW,
 			"SiRF: NTPD just SEEN_UTC_2\n");
@@ -988,7 +988,7 @@ static gps_mask_t sirf_msg_ublox(struct gps_device_t *session,
 		    "SiRF: NTPD valid time MID 0x62, seen=0x%02x\n",
 		    session->driver.sirf.time_seen);
 	session->driver.sirf.time_seen |= TIME_SEEN_UTC_2;
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
 	session->context->valid |= LEAP_SECOND_VALID;
     }
 
@@ -1034,7 +1034,7 @@ static gps_mask_t sirf_msg_ppstime(struct gps_device_t *session,
 	/*@ +compdef */
 	session->context->leap_seconds = (int)getbeu16(buf, 8);
 	session->context->valid |= LEAP_SECOND_VALID;
-#ifdef NTPSHM_ENABLE
+#ifdef TIMEHINT_ENABLE
 	if (0 == (session->driver.sirf.time_seen & TIME_SEEN_UTC_2)) {
 	    gpsd_report(session->context->debug, LOG_RAW,
 			"SiRF: NTPD just SEEN_UTC_2\n");
@@ -1044,7 +1044,7 @@ static gps_mask_t sirf_msg_ppstime(struct gps_device_t *session,
 		    session->driver.sirf.time_seen,
 		    session->context->leap_seconds);
 	session->driver.sirf.time_seen |= TIME_SEEN_UTC_2;
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
 	mask |= TIME_SET;
 	if ( 3 <= session->gpsdata.satellites_visible ) {
 	    mask |= PPSTIME_IS;
@@ -1385,8 +1385,8 @@ const struct gps_type_t sirf_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = sirf_control_send,/* how to send a control string */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = sirf_ntp_offset,
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = sirf_time_offset,
 #endif /* NTP_SHM_ENABLE */
 };
 /* *INDENT-ON* */
diff --git a/driver_superstar2.c b/driver_superstar2.c
index 31a8658c..9761c824 100644
--- a/driver_superstar2.c
+++ b/driver_superstar2.c
@@ -575,9 +575,9 @@ const struct gps_type_t superstar2_binary = {
     /* Control string sender - should provide checksum and trailer */
     .control_send	= superstar2_control_send,
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* defined(SUPERSTAR2_ENABLE) && defined(BINARY_ENABLE) */
diff --git a/driver_tsip.c b/driver_tsip.c
index 087dfccf..6dced174 100644
--- a/driver_tsip.c
+++ b/driver_tsip.c
@@ -1151,13 +1151,13 @@ static void tsip_mode(struct gps_device_t *session, int mode)
 }
 #endif /* RECONFIGURE_ENABLE */
 
-#ifdef NTPSHM_ENABLE
-static double tsip_ntp_offset(struct gps_device_t *session UNUSED)
+#ifdef TIMEHINT_ENABLE
+static double tsip_time_offset(struct gps_device_t *session UNUSED)
 {
     /* FIX-ME: is a constant offset right here? */
     return 0.075;
 }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
 
 void configuration_packets_generic(struct gps_device_t *session)
 /* configure generic Trimble TSIP device to a known state */
@@ -1274,9 +1274,9 @@ const struct gps_type_t tsip_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = tsip_control_send,/* how to send commands */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = tsip_ntp_offset,
-#endif /* NTPSHM_ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = tsip_time_offset,
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 
diff --git a/driver_ubx.c b/driver_ubx.c
index d1bda91d..feb14b11 100644
--- a/driver_ubx.c
+++ b/driver_ubx.c
@@ -840,9 +840,9 @@ const struct gps_type_t ubx_binary = {
 #ifdef CONTROLSEND_ENABLE
     .control_send     = ubx_control_send,	/* no control sender yet */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* defined(UBX_ENABLE) && defined(BINARY_ENABLE) */
diff --git a/driver_zodiac.c b/driver_zodiac.c
index 296dbece..14e15f28 100644
--- a/driver_zodiac.c
+++ b/driver_zodiac.c
@@ -445,8 +445,8 @@ static bool zodiac_speed_switch(struct gps_device_t *session,
 }
 #endif /* RECONFIGURE_ENABLE */
 
-#ifdef NTPSHM_ENABLE
-static double zodiac_ntp_offset(struct gps_device_t *session UNUSED)
+#ifdef TIMEHINT_ENABLE
+static double zodiac_time_offset(struct gps_device_t *session UNUSED)
 {
     /* Removing/changing the magic number below is likely to disturb
      * the handling of the 1pps signal from the gps device. The regression
@@ -454,7 +454,7 @@ static double zodiac_ntp_offset(struct gps_device_t *session UNUSED)
      * with the 1pps signal active is required. */
     return 1.1;
 }
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
 
 /* this is everything we export */
 /* *INDENT-OFF* */
@@ -479,9 +479,9 @@ const struct gps_type_t zodiac_binary =
 #ifdef CONTROLSEND_ENABLE
     .control_send   = zodiac_control_send,	/* for gpsctl and friends */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = zodiac_ntp_offset,	/* compute NTO fudge factor */
-#endif /* NTPSHM_ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = zodiac_time_offset,	/* compute NTO fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 
diff --git a/drivers.c b/drivers.c
index b6727417..90eb5689 100644
--- a/drivers.c
+++ b/drivers.c
@@ -101,9 +101,9 @@ const struct gps_type_t unknown = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = NULL,		/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 
@@ -265,9 +265,9 @@ const struct gps_type_t nmea = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 
@@ -366,9 +366,9 @@ const struct gps_type_t garmin = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* GARMIN_ENABLE && NMEA_ENABLE */
@@ -428,9 +428,9 @@ const struct gps_type_t ashtech = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* ASHTECH_ENABLE */
@@ -479,9 +479,9 @@ const struct gps_type_t fv18 = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* FV18_ENABLE */
@@ -533,9 +533,9 @@ const struct gps_type_t gpsclock = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* GPSCLOCK_ENABLE */
@@ -588,9 +588,9 @@ static const struct gps_type_t tripmate = {
 #ifdef CONTROLSEND_ENABLE
     .control_send  = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* TRIPMATE_ENABLE */
@@ -639,9 +639,9 @@ static const struct gps_type_t earthmate = {
 #ifdef CONTROLSEND_ENABLE
     .control_send  = nmea_write,	/* never actually used. */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /*@ -redef @*/
 /* *INDENT-ON* */
@@ -762,9 +762,9 @@ const struct gps_type_t trueNorth = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = tnt_control_send,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif
@@ -840,9 +840,9 @@ static const struct gps_type_t oceanServer = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif
@@ -907,9 +907,9 @@ static const struct gps_type_t fury = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 
@@ -961,9 +961,9 @@ static const struct gps_type_t rtcm104v2 = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = NULL,		/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* RTCM104V2_ENABLE */
@@ -1007,9 +1007,9 @@ static const struct gps_type_t rtcm104v3 = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = NULL,		/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* RTCM104V3_ENABLE */
@@ -1042,9 +1042,9 @@ static const struct gps_type_t garmintxt = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = NULL,		/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* GARMINTXT_ENABLE */
@@ -1136,9 +1136,9 @@ const struct gps_type_t mtk3301 = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = nmea_write,	/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* MTK3301_ENABLE */
@@ -1374,9 +1374,9 @@ const struct gps_type_t aivdm = {
 #ifdef CONTROLSEND_ENABLE
     .control_send     = NULL,		/* no control sender */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no NTP communication */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no NTP communication */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 #endif /* AIVDM_ENABLE */
@@ -1472,9 +1472,9 @@ const struct gps_type_t json_passthrough = {
 #ifdef CONTROLSEND_ENABLE
     .control_send   = NULL,		/* how to send control strings */
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    .ntp_offset     = NULL,		/* no method for NTP fudge factor */
-#endif /* NTPSHM_ ENABLE */
+#ifdef TIMEHINT_ENABLE
+    .time_offset     = NULL,		/* no method for NTP fudge factor */
+#endif /* TIMEHINT_ENABLE */
 };
 /* *INDENT-ON* */
 
diff --git a/gpscap.ini b/gpscap.ini
index 533150e4..8c2bc308 100644
--- a/gpscap.ini
+++ b/gpscap.ini
@@ -24,7 +24,7 @@
 # usbchip      = USB I/O chipset
 # pps	       = supports pulse-per-second precision time reporting
 # pps_accuracy = claimed PPS accuracy
-# ntp_offset   = NTP offset
+# time_offset   = NTP offset
 # configurable = can the device be bricked by speed changes?
 # tested       = last gpsd tested, or "regression" if we have a test load
 # nmea	       = NMEA version this emits, if known
@@ -871,7 +871,7 @@ nmea = 2.0 and 2.3
 packaging = mouse
 pps = True
 pps_accuracy = 1us
-ntp_offset = 0.125s
+time_offset = 0.125s
 submitter = Gary E. Miller <gem@rellim.com>
 techdoc = http://www.garmin.com/manuals/GPS18_TechnicalSpecification.pdf
 tested = 2.5
@@ -1162,7 +1162,7 @@ nmea = 3.01
 packaging = mouse
 pps = True
 pps_accuracy = 50ns
-ntp_offset = ?
+time_offset = ?
 rating = excellent
 submitter = Gary E. Miller <gem@rellim.com>, Tony Hain <tony@tndh.net>
 techdoc = http://www.usglobalsat.com/p-58-mr-350p-bulkhead.aspx
@@ -1425,7 +1425,7 @@ firmware = 2.18
 interfaces = RS-232
 pps = True
 pps_accuracy = 50ns
-ntp_offset = ?
+time_offset = ?
 model = FireFly-1A and FireFly-II GPSDO
 notes = Uses uBlox Antaris 5 with Kick Start and Super Sense, 
         soon movingto uBlox-6.  Defective \r\r\n string terminations
@@ -1530,7 +1530,7 @@ tested = regression
 rating = good
 pps = True
 pps_accuracy = 250ns
-ntp_offset = ?
+time_offset = ?
 submitter = Chris Kuethe <chris.kuethe@gmail.com>
 notes = Receiver comes up in silent mode, you may need to use ashctl to turn
       on a default set of messages. Tested with firmware BQ00 and BQ04.
@@ -1565,7 +1565,7 @@ tested = 2.20
 nmea = 2.2
 pps = True
 pps_accuracy = 50ns
-ntp_offset = ?
+time_offset = ?
 rating = good
 discontinued = True
 submitter = Wojciech Kazubski <wk@ire.pw.edu.pl>
@@ -1612,7 +1612,7 @@ interfaces = USB
 tested = 3.9
 pps = True
 pps_accuracy = 1ms
-ntp_offset = ?
+time_offset = ?
 rating = excellent
 submitter = Eric S. Raymond <esr@thyrsus.com>.
 notes = Also known as the Macx-1, this is the USB variant of the
@@ -2266,7 +2266,7 @@ engine = Colossus RF ASIC, IO-C33 (Epson C33 RISC)
 interfaces = USB,RS-232
 pps = True
 pps_accuracy = 50ns
-ntp_offset = 0.675s
+time_offset = 0.675s
 usbchip = CP2102
 tested = regression
 rating = good
@@ -2332,7 +2332,7 @@ interfaces = USB,UART
 tested = regression
 pps = True
 pps_accuracy = 50ns
-ntp_offset = ?
+time_offset = ?
 submitter = Chris Kuethe <chris.kuethe@gmail.com>
 
 [EVK-5H-0]
@@ -2355,7 +2355,7 @@ date = 2011-02-02
 interfaces = TTL
 pps = True
 pps_accuracy = 50ns
-ntp_offset = ?
+time_offset = ?
 location = Adelaide, AU, 34.9S, 138.6E
 model = LEA 5Q
 notes = Sample contains GPGST (pseudorange noise statistics).
@@ -2379,7 +2379,7 @@ model = EVK-6H-0
 packaging = other
 rating = excellent
 pps_accuracy = 50ns
-ntp_offset = ?
+time_offset = ?
 submitter = Eric S. Raymond <esr@thyrsus.com>
 techdoc = http://www.u-blox.com/images/downloads/Product_Docs/u-blox6_ReceiverDescriptionProtocolSpec_%28GPS.G6-SW-10018%29.pdf
 vendor = uBlox
diff --git a/gpscap.py b/gpscap.py
index b00f46c7..423cea17 100644
--- a/gpscap.py
+++ b/gpscap.py
@@ -139,13 +139,13 @@ class GPSDictionary(ConfigParser.RawConfigParser):
                     nmea = self.get(dev, "nmea")
                 ofp.write("<td>%s</td>\n" % nmea)
                 if self.has_option(dev, "pps") and self.get(dev, "pps") == "True":
-                    pps_accuracy = ntp_offset = ""
+                    pps_accuracy = time_offset = ""
                     if self.has_option(dev, "pps_accuracy"):
                         pps_accuracy = self.get(dev, "pps_accuracy")
-                    if self.has_option(dev, "ntp_offset"):
-                        ntp_offset = self.get(dev, "ntp_offset")
-                    if pps_accuracy and ntp_offset:
-                        ofp.write("<td>%s<br>%s</td>\n" % (pps_accuracy, ntp_offset))
+                    if self.has_option(dev, "time_offset"):
+                        time_offset = self.get(dev, "time_offset")
+                    if pps_accuracy and time_offset:
+                        ofp.write("<td>%s<br>%s</td>\n" % (pps_accuracy, time_offset))
                     else:
                         ofp.write("<td>?<br>\n")
                 else:
diff --git a/gpsd.c b/gpsd.c
index ea680866..6c13d563 100644
--- a/gpsd.c
+++ b/gpsd.c
@@ -220,8 +220,8 @@ static void typelist(void)
 #if defined(DBUS_EXPORT_ENABLE)
     (void)printf("# DBUS export enabled\n");
 #endif
-#if defined(NTPSHM_ENABLE)
-    (void)printf("# NTPSHM for NTPd enabled.\n");
+#if defined(TIMEHINT_ENABLE)
+    (void)printf("# Time service features enabled.\n");
 #endif
 #if defined(PPS_ENABLE)
     (void)printf("# PPS enabled.\n");
@@ -1536,10 +1536,10 @@ static void all_reports(struct gps_device_t *device, gps_mask_t changed)
 	//gpsd_report(context.debug, LOG_PROG, "NTP: Got one\n");
 	/* assume zero when there's no offset method */
 	if (device->device_type == NULL
-	    || device->device_type->ntp_offset == NULL)
+	    || device->device_type->time_offset == NULL)
 	    offset = 0.0;
 	else
-	    offset = device->device_type->ntp_offset(device);
+	    offset = device->device_type->time_offset(device);
 	(void)ntpshm_put(device, device->newdata.time, offset);
 	device->last_fixtime = device->newdata.time;
     }
diff --git a/gpsd.h-tail b/gpsd.h-tail
index f555fda9..87c31386 100644
--- a/gpsd.h-tail
+++ b/gpsd.h-tail
@@ -83,6 +83,9 @@ typedef unsigned int speed_t;
 #if defined(TNT_ENABLE) || defined(OCEANSERVER_ENABLE)
 #define COMPASS_ENABLE
 #endif
+#ifdef NTPSHM_ENABLE
+#define TIMEHINT_ENABLE
+#endif
 
 /* First, declarations for the packet layer... */
 
@@ -239,7 +242,7 @@ struct gps_context_t {
     double gps_tow;                     /* GPS time of week, actually 19 bits */
     int century;			/* for NMEA-only devices without ZDA */
     int rollovers;			/* rollovers since start of run */
-#ifdef NTPSHM_ENABLE
+#ifdef TIMEHINT_ENABLE
     int leap_notify;			/* notification state from subframe */
 #define LEAP_NOWARNING  0x0     /* normal, no leap second warning */
 #define LEAP_ADDSECOND  0x1     /* last minute of day has 60 seconds */
@@ -250,7 +253,7 @@ struct gps_context_t {
      * 'optimize' as 'dead code' the writes to SHM */
     /*@reldef@*/volatile struct shmTime *shmTime[NTPSHMSEGS];
     bool shmTimeInuse[NTPSHMSEGS];
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
 # ifdef PPS_ENABLE
     /*@null@*/ void (*pps_hook)(struct gps_device_t *,
 				unsigned long, struct timespec *);
@@ -348,9 +351,9 @@ struct gps_type_t {
 #ifdef CONTROLSEND_ENABLE
     /*@null@*/ssize_t (*control_send)(struct gps_device_t *session, char *buf, size_t buflen);
 #endif /* CONTROLSEND_ENABLE */
-#ifdef NTPSHM_ENABLE
-    /*@null@*/double (*ntp_offset)(struct gps_device_t *session);
-#endif /* NTPSHM_ENABLE */
+#ifdef TIMEHINT_ENABLE
+    /*@null@*/double (*time_offset)(struct gps_device_t *session);
+#endif /* TIMEHINT_ENABLE */
 };
 
 /*
diff --git a/libgpsd_core.c b/libgpsd_core.c
index 4a3a92e6..efc026d2 100644
--- a/libgpsd_core.c
+++ b/libgpsd_core.c
@@ -231,8 +231,10 @@ void gps_context_init(struct gps_context_t *context)
 	.gps_tow        = 0,
 	.century	= 0,
 	.rollovers      = 0,
-#ifdef NTPSHM_ENABLE
+#ifdef TIMEHINT_ENABLE
 	.leap_notify    = LEAP_NOWARNING,
+#endif /* TIMEHINT_ENABLE */
+#ifdef NTPSHM_ENABLE
 	.enable_ntpshm  = false,
 	.shmTime	= {0},
 	.shmTimeInuse   = {0},
diff --git a/subframe.c b/subframe.c
index 25097428..eaf34779 100644
--- a/subframe.c
+++ b/subframe.c
@@ -728,7 +728,7 @@ gps_mask_t gpsd_interpret_subframe(struct gps_device_t *session,
 			    subp->sub4_18.leap, subp->sub4_18.WNlsf,
 			    subp->sub4_18.DN, subp->sub4_18.lsf);
 
-#ifdef NTPSHM_ENABLE
+#ifdef TIMEHINT_ENABLE
 		/* IS-GPS-200 Revision E, paragraph 20.3.3.5.2.4 */
 		if (((session->context->gps_week % 256) == (unsigned short)subp->sub4_18.WNlsf) &&
 		    /* notify the leap seconds correction in the end of current day */
@@ -742,7 +742,7 @@ gps_mask_t gpsd_interpret_subframe(struct gps_device_t *session,
 			session->context->leap_notify = LEAP_NOWARNING;
 		} else
 		   session->context->leap_notify = LEAP_NOWARNING;
-#endif /* NTPSHM_ENABLE */
+#endif /* TIMEHINT_ENABLE */
 
 		session->context->leap_seconds = (int)subp->sub4_18.leap;
 		session->context->valid |= LEAP_SECOND_VALID;
diff --git a/www/writing-a-driver.xml b/www/writing-a-driver.xml
index ab624354..91e751b4 100644
--- a/www/writing-a-driver.xml
+++ b/www/writing-a-driver.xml
@@ -15,6 +15,14 @@
 
 <revhistory>
    <revision>
+      <revnumber>1.12</revnumber>
+      <date>31 Oct 2013</date>
+      <authorinitials>er</authorinitials>
+      <revremark>
+	 Updated by esr; ntp_offset becomes time_offset
+      </revremark>
+   </revision>
+   <revision>
       <revnumber>1.11</revnumber>
       <date>19 Jan 2011</date>
       <authorinitials>er</authorinitials>
@@ -745,11 +753,12 @@ possible, assemble your packet in
 gpsmon to display the control messages it sends for you.</para>
 
 <!-- added by ESR, 2009 -->
-<para><structfield>.ntp_offset</structfield> points to code to compute
-an offset to be added, additionally to that in
-<filename>ntp.conf</filename> (if any) when shipping time notifications
-to NTP. If multiple sentences set TIME_IS, this will differ by
-sentence type; it should differ by baud rare, as well. </para>
+<para><structfield>.timr_offset</structfield> points to code to
+compute an offset to be added, additionally to that in
+<filename>ntp.conf</filename> (if any) when shipping time
+notifications to NTP, or the equivalent configuration file for
+chrony. If multiple sentences set TIME_IS, this will differ by
+sentence type; it should differ by baud rate, as well. </para>
 
 </sect1>