dvb: Better handling of uncorrected blocks counter

Some DVB adapters return delta value from last read. Some return absolute value since adapter was created. Add some heuristics that tries to autodetect this. Ticket tvheadend#393
romanlum · May 3, 2011 · c26a0b4 · c26a0b4
1 parent 935114b
commit c26a0b4
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Showing 2 changed files with 48 additions and 10 deletions.
diff --git a/src/dvb/dvb.h b/src/dvb/dvb.h
@@ -200,6 +200,11 @@ typedef struct th_dvb_adapter {
   int tda_allpids_dmx_fd;
   int tda_dump_fd;
 
+  uint32_t tda_last_fec;
+
+  int tda_unc_is_delta;  /* 1 if we believe FE_READ_UNCORRECTED_BLOCKS
+			  * return dela values */
+
 } th_dvb_adapter_t;
 
 

diff --git a/src/dvb/dvb_fe.c b/src/dvb/dvb_fe.c
@@ -40,6 +40,42 @@
 #include "notify.h"
 #include "dvr/dvr.h"
 
+/**
+ * Return uncorrected block (since last read)
+ *
+ * Some adapters report delta themselfs, some return ever increasing value
+ * we need to deal with that ourselfs
+ */
+static int
+dvb_fe_get_unc(th_dvb_adapter_t *tda)
+{
+  uint32_t fec;
+  int d, r;
+
+  if(ioctl(tda->tda_fe_fd, FE_READ_UNCORRECTED_BLOCKS, &fec))
+    return 0; // read failed, just say 0
+
+  if(tda->tda_unc_is_delta)
+    return fec;
+
+  d = (int)fec - (int)tda->tda_last_fec;
+
+  if(d < 0) {
+    tda->tda_unc_is_delta = 1;
+    tvhlog(LOG_DEBUG, "dvb",
+	   "%s: FE_READ_UNCORRECTED_BLOCKS returns delta updates (delta=%d)",
+	   tda->tda_displayname, d);
+    return fec;
+  }
+
+  r = fec - tda->tda_last_fec;
+
+  tda->tda_last_fec = fec;
+  return r;
+}
+
+
+
 /**
  * Front end monitor
  *
@@ -79,7 +115,7 @@ dvb_fe_monitor(void *aux)
     if(status == -1) { /* We have a lock, don't hold off */
       tda->tda_fe_monitor_hold = 0; 
       /* Reset FEC counter */
-      ioctl(tda->tda_fe_fd, FE_READ_UNCORRECTED_BLOCKS, &fec);
+      dvb_fe_get_unc(tda);
     } else {
       tda->tda_fe_monitor_hold--;
       return;
@@ -89,8 +125,7 @@ dvb_fe_monitor(void *aux)
   if(status == -1) {
     /* Read FEC counter (delta) */
 
-    if(ioctl(tda->tda_fe_fd, FE_READ_UNCORRECTED_BLOCKS, &fec))
-      fec = 0;
+    fec = dvb_fe_get_unc(tda);
 
     tdmi->tdmi_fec_err_histogram[tdmi->tdmi_fec_err_ptr++] = fec;
     if(tdmi->tdmi_fec_err_ptr == TDMI_FEC_ERR_HISTOGRAM_SIZE)
@@ -277,7 +312,7 @@ static int check_frontend (int fe_fd, int dvr, int human_readable) {
   (void)dvr;
   fe_status_t status;
   uint16_t snr, signal;
-  uint32_t ber, uncorrected_blocks;
+  uint32_t ber;
   int timeout = 0;
 
   do {
@@ -292,15 +327,13 @@ static int check_frontend (int fe_fd, int dvr, int human_readable) {
       snr = -2;
     if (ioctl(fe_fd, FE_READ_BER, &ber) == -1)
       ber = -2;
-    if (ioctl(fe_fd, FE_READ_UNCORRECTED_BLOCKS, &uncorrected_blocks) == -1)
-      uncorrected_blocks = -2;
 
     if (human_readable) {
-      printf ("status %02x | signal %3u%% | snr %3u%% | ber %d | unc %d | ",
-          status, (signal * 100) / 0xffff, (snr * 100) / 0xffff, ber, uncorrected_blocks);
+      printf ("status %02x | signal %3u%% | snr %3u%% | ber %d | ",
+          status, (signal * 100) / 0xffff, (snr * 100) / 0xffff, ber);
     } else {
-      printf ("status %02x | signal %04x | snr %04x | ber %08x | unc %08x | ",
-          status, signal, snr, ber, uncorrected_blocks);
+      printf ("status %02x | signal %04x | snr %04x | ber %08x | ",
+          status, signal, snr, ber);
     }
     if (status & FE_HAS_LOCK)
       printf("FE_HAS_LOCK");