Commit 74563214 authored Oct 15, 2008 by Christophe Thommeret Committed by Mauro Carvalho Chehab Oct 17, 2008

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>

parent 430189da

drivers/media/dvb/frontends/cx24116.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -1248,7 +1248,10 @@ static int cx24116_set_frontend(struct dvb_frontend *fe,

		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;