[media] DiB8000: improve the tuning and the SNR monitoring

This patches improves the tuning of the dib8000 and correct the monitoringr
of the SNR.The patch allows to faster detect that there is no ISDB-T channel
on the wanted frequency.
Signed-off-by: NOlivier Grenie <olivier.grenie@dibcom.fr>
Signed-off-by: NPatrick Boettcher <patrick.boettcher@dibcom.fr>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/frontends/dib8000.c

@@ -2215,7 +2215,7 @@ static int dib8000_set_frontend(struct dvb_frontend *fe, struct dvb_frontend_par
 			 ((state->fe[0]->dtv_property_cache.layer[1].segment_count == 0) ||
 			  ((state->fe[0]->dtv_property_cache.isdbt_layer_enabled & (2 << 0)) == 0)) &&
 			 ((state->fe[0]->dtv_property_cache.layer[2].segment_count == 0) || ((state->fe[0]->dtv_property_cache.isdbt_layer_enabled & (3 << 0)) == 0)))) {
-		int i = 80000;
+		int i = 100;
 		u8 found = 0;
 		u8 tune_failed = 0;
 
@@ -2243,6 +2243,7 @@ static int dib8000_set_frontend(struct dvb_frontend *fe, struct dvb_frontend_par
 					default:
 						 dprintk("unhandled autosearch result");
 					case 1:
+						 tune_failed |= (1 << index_frontend);
 						 dprintk("autosearch failed for the frontend%i", index_frontend);
 						 break;
 					}
@@ -2401,7 +2402,7 @@ static int dib8000_read_snr(struct dvb_frontend *fe, u16 * snr)
 	for (index_frontend = 1; (index_frontend < MAX_NUMBER_OF_FRONTENDS) && (state->fe[index_frontend] != NULL); index_frontend++)
 		snr_master += dib8000_get_snr(state->fe[index_frontend]);
 
-	if (snr_master != 0) {
+	if ((snr_master >> 16) != 0) {
 		snr_master = 10*intlog10(snr_master>>16);
 		*snr = snr_master / ((1 << 24) / 10);
 	}