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| author | Eric S. Raymond <esr@thyrsus.com> | 2005-06-19 16:47:35 +0000 |
|---|---|---|
| committer | Eric S. Raymond <esr@thyrsus.com> | 2005-06-19 16:47:35 +0000 |
| commit | e39f39a63a649f8de6f06717302c37c493c8e4f0 (patch) | |
| tree | 234f5deeb5131c4c6a9feb8e0292bb302e686ea5 | |
| parent | 42ccfb24f6f0fedcdc4927ed320538404dfcab17 (diff) | |
| download | gpsd-e39f39a63a649f8de6f06717302c37c493c8e4f0.tar.gz | |
Avoid CPU cost for nonworking DCD change detection.
| -rw-r--r-- | libgpsd_core.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/libgpsd_core.c b/libgpsd_core.c index 2a10c312..4b9dc5b8 100644 --- a/libgpsd_core.c +++ b/libgpsd_core.c @@ -111,7 +111,7 @@ void gpsd_deactivate(struct gps_device_t *session) static void *gpsd_ppsmonitor(void *arg) { struct gps_device_t *session = (struct gps_device_t *)arg; - int cycle,duration, state = 0; + int cycle,duration, state = 0, laststate = -1, unchanged = 0; struct timeval tv; struct timeval pulse[2] = {{0,0},{0,0}}; @@ -124,8 +124,18 @@ static void *gpsd_ppsmonitor(void *arg) /*@ -ignoresigns */ state = (int)((state & TIOCM_CAR) != 0); - gpsd_report(5, "carrier-detect on %s changed to %d\n", - session->gpsdata.gps_device, state); + + if (state == laststate) { + if (++unchanged == 10) { + gpsd_report(1, "TIOCMIWAIT returns unchanged state, ppsmonitor terminates\n"); + break; + } + } else { + gpsd_report(5, "carrier-detect on %s changed to %d\n", + session->gpsdata.gps_device, state); + laststate = state; + unchanged = 0; + } /*@ +boolint @*/ if (session->gpsdata.fix.mode > MODE_NO_FIX) { |