mpegts network_scan: fix problems with having multiple networks

previously as soon as any mux failed it would give up assuming nothing else
could be tuned. However just because no tuner was available that could service
that mux doesn't mean there wasn't one that couldn't service another.

The only real issue I can see with this is if we're idle scanning it's possible
due to bad luck to starve muxes of an attempt. We can either rely on random
chance or put some additional weighting based on time? Though that could be
problematic for other reasons.

src/input/mpegts/mpegts_network_scan.c

@@ -60,16 +60,14 @@ mpegts_network_scan_timer_arm ( int period )
 static void
 mpegts_network_scan_timer_cb ( void *p )
 {
-  mpegts_mux_t *mm, *mark = NULL;
+  mpegts_mux_t *mm, *nxt = NULL;
   int r;
 
   /* Process Q */
-  while ((mm = TAILQ_FIRST(&mpegts_network_scan_pend))) {
+  for (mm = TAILQ_FIRST(&mpegts_network_scan_pend); mm != NULL; mm = nxt) {
+    nxt = TAILQ_NEXT(mm, mm_scan_link);
     assert(mm->mm_scan_state == MM_SCAN_STATE_PEND);
 
-    /* Stop (looped) */
-    if (mm == mark) break;
-
     /* Attempt to tune */
     r = mpegts_mux_subscribe(mm, "scan", mm->mm_scan_weight);
 
@@ -80,23 +78,16 @@ mpegts_network_scan_timer_cb ( void *p )
     }
     assert(mm->mm_scan_state == MM_SCAN_STATE_PEND);
 
-    /* Stop (no free tuners) */
-    if (r == SM_CODE_NO_FREE_ADAPTER)
-      break;
-
-    /* Available tuners can't be used
-     * Note: this is subtly different it does not imply there are no free
-     *       tuners, just that none of the free ones can service this mux.
-     *       therefore we move this to the back of the queue and see if we
-     *       can find one we can tune
+    /* Either there are no free tuners, or no valid tuners
+     *
+     * Although these are subtly different, the reality is that in this
+     * context we need to treat each the same. We simply skip over this
+     * mux and see if anything else can be tuned as it may use other 
+     * tuners
      */
-    if (r == SM_CODE_NO_VALID_ADAPTER) {
-      if (!mark) mark = mm;
-      TAILQ_REMOVE(&mpegts_network_scan_pend, mm, mm_scan_link);
-      TAILQ_INSERT_SORTED_R(&mpegts_network_scan_pend, mpegts_mux_queue,
-                            mm, mm_scan_link, mm_cmp);
+    if (r == SM_CODE_NO_FREE_ADAPTER ||
+        r == SM_CODE_NO_VALID_ADAPTER)
       continue;
-    }
 
     /* Failed */
     TAILQ_REMOVE(&mpegts_network_scan_pend, mm, mm_scan_link);
@@ -105,13 +96,14 @@ mpegts_network_scan_timer_cb ( void *p )
       mm->mm_config_save(mm);
     }
     mm->mm_scan_state  = MM_SCAN_STATE_IDLE;
+    mm->mm_scan_weight = 0;
     mpegts_network_scan_notify(mm);
   }
 
-  /* Re-arm (backstop, most things will auto-rearm at point of next event
-   * such as timeout of scan or completion)
+  /* Re-arm timer. Really this is just a safety measure as we'd normally
+   * expect the timer to be forcefully triggered on finish of a mux scan
    */
-  mpegts_network_scan_timer_arm(10);
+  mpegts_network_scan_timer_arm(120);
 }
 
 /******************************************************************************
@@ -194,7 +186,8 @@ mpegts_network_scan_queue_del ( mpegts_mux_t *mm )
   } else if (mm->mm_scan_state == MM_SCAN_STATE_PEND) {
     TAILQ_REMOVE(&mpegts_network_scan_pend, mm, mm_scan_link);
   }
-  mm->mm_scan_state = MM_SCAN_STATE_IDLE;
+  mm->mm_scan_state  = MM_SCAN_STATE_IDLE;
+  mm->mm_scan_weight = 0;
   gtimer_disarm(&mm->mm_scan_timeout);
   mpegts_network_scan_timer_arm(0);
   mpegts_network_scan_notify(mm);
@@ -204,6 +197,7 @@ void
 mpegts_network_scan_queue_add ( mpegts_mux_t *mm, int weight )
 {
   int reload = 0;
+  char buf[256];
 
   if (!mm->mm_is_enabled(mm)) return;
 
@@ -225,6 +219,9 @@ mpegts_network_scan_queue_add ( mpegts_mux_t *mm, int weight )
     TAILQ_REMOVE(&mpegts_network_scan_pend, mm, mm_scan_link);
   }
 
+  mm->mm_display_name(mm, buf, sizeof(buf));
+  tvhdebug("mpegts", "adding mux %p:%s to queue weight %d", mm, buf, weight);
+
   /* Add new entry */
   mm->mm_scan_state = MM_SCAN_STATE_PEND;
   TAILQ_INSERT_SORTED_R(&mpegts_network_scan_pend, mpegts_mux_queue,