1 files changed, 8 insertions, 3 deletions
diff --git a/libgpsd_core.c b/libgpsd_core.c
index 306bca13..c6ced73d 100644
--- a/libgpsd_core.c
+++ b/libgpsd_core.c
@@ -899,9 +899,14 @@ static void gpsd_error_model(struct gps_device_t *session,
      * expected time error should be half the resolution of
      * the GPS clock, so we put the bound of the error
      * in as a constant pending getting it from each driver.
-     * FIXME: increase this if no leap-second has been seen
-     * and it's less than 750s (one almanac load cycle)
-     * from device powerup.
+     *
+     * In an ideal world, we'd increase this if no leap-second has
+     * been seen and it's less than 750s (one almanac load cycle) from
+     * device powerup. Alas, we have no way to know when device
+     * powerup occurred - depending on the receiver design it could be
+     * when the hardware was first powered up or when it was first
+     * opened.  Also, some devices (notably plain NMEA0183 receivers)
+     * never ship an indication of when they have valid leap second.
      */
     if (isnan(fix->time) == 0 && isnan(fix->ept) != 0)
 	fix->ept = 0.005;