linuxdvb: allow to force using old linuxdvb ioctls, fixes#2759

docs/html/config_tvadapters.html

@@ -89,6 +89,11 @@ The rows have the following functions
       In this case, increase the default value. For fast hardware, this value
       might be descreased to make the decision of the re-tune algorithm
       based on the signal status faster.</dd>
+<p>
+ <dt><b>Force old status</b></dt>
+  <dd>Always use the old ioctls to read the linuxdvb status (signal strenght,
+      SNR, error counters). Some drivers are not matured enough to provide
+      the correct values using the new v5 linuxdvb API.</dd>
 </dl>
 
 <br>

src/input/mpegts/linuxdvb/linuxdvb_frontend.c

@@ -120,6 +120,13 @@ const idclass_t linuxdvb_frontend_class =
       .opts     = PO_ADVANCED,
       .off      = offsetof(linuxdvb_frontend_t, lfe_status_period),
     },
+    {
+      .type     = PT_BOOL,
+      .id       = "old_status",
+      .name     = "Force old status",
+      .opts     = PO_ADVANCED,
+      .off      = offsetof(linuxdvb_frontend_t, lfe_old_status),
+    },
     {}
   }
 };
@@ -649,7 +656,8 @@ linuxdvb_frontend_monitor ( void *aux )
 
   logit = tvhlog_limit(&lfe->lfe_status_log, 3600);
 
-  if(ioctl_check(lfe, 0) && !ioctl(lfe->lfe_fe_fd, FE_GET_PROPERTY, &dtv_prop)) {
+  if(ioctl_check(lfe, 0) && !lfe->lfe_old_status &&
+     !ioctl(lfe->lfe_fe_fd, FE_GET_PROPERTY, &dtv_prop)) {
     /* Signal strength */
     gotprop = 0;
     if(ioctl_check(lfe, 1) && fe_properties[0].u.st.len > 0) {

src/input/mpegts/linuxdvb/linuxdvb_private.h

@@ -118,6 +118,7 @@ struct linuxdvb_frontend
   uint32_t                  lfe_skip_bytes;
   uint32_t                  lfe_ibuf_size;
   uint32_t                  lfe_status_period;
+  int                       lfe_old_status;
 
   /*
    * Satconf (DVB-S only)