V4L/DVB (9270): cx24116: optimise emulated auto-pilot
Christophe divulged the following:
"Since 8PSK (and higher mod) signals are very likely to have pilot symbols,
pilot_auto should start with pilot_on for 8PSK.
And since QPSK signals are unlikely to have pilot, pilot_auto should start
with pilot_off for QPSK.
Without the patch:
QPSK tuning delay: ~100ms
8PSK tuning delay: ~900ms
with patch:
QPSK tuning delay: ~100ms
8PSK tuning delay: ~100ms
"
This patch does as Cristophe asks. In emulated auto-pilot we
choose pilot-on for tuning PSK_8 and pilot-off for
tuning QPSK.
Signed-off-by: Darron Broad <darron@kewl.org>
Signed-off-by: Steven Toth <stoth@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/dvb/frontends/cx24116.c b/drivers/media/dvb/frontends/cx24116.c
index 8afdfbe..fe62f92 100644
--- a/drivers/media/dvb/frontends/cx24116.c
+++ b/drivers/media/dvb/frontends/cx24116.c
@@ -1248,7 +1248,10 @@
switch (c->pilot) {
case PILOT_AUTO: /* Not supported but emulated */
- retune = 2; /* Fall-through */
+ state->dnxt.pilot_val = (c->modulation == QPSK)
+ ? CX24116_PILOT_OFF : CX24116_PILOT_ON;
+ retune = 2;
+ break;
case PILOT_OFF:
state->dnxt.pilot_val = CX24116_PILOT_OFF;
break;