From 50eac6bc466f69e1ecb3a1b64346ed7b979547ac Mon Sep 17 00:00:00 2001 From: Devin Heitmueller Date: Mon, 20 Oct 2008 10:19:07 -0300 Subject: V4L/DVB (9315): s5h1411: Skip reconfiguring demod modulation if already at the desired modulation If we are already at the desired modulation, there is no need to reconfigure the demod (at a tuning time cost) Note that this change revealed that although the datasheet says the demod starts out in VSB-8 mode, the first tuning was failing consistently unless we went through the work of setting the registers. So add a field to denote this case so we always do the enable_frontend call, even if the first tuning request is for VSB-8. Signed-off-by: Devin Heitmueller Reviewed-by: Michael Krufky Acked-by: Steven Toth Signed-off-by: Mauro Carvalho Chehab --- drivers/media/dvb/frontends/s5h1411.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'drivers/media/dvb') diff --git a/drivers/media/dvb/frontends/s5h1411.c b/drivers/media/dvb/frontends/s5h1411.c index 40e0fedf381..b9ac6d35a1e 100644 --- a/drivers/media/dvb/frontends/s5h1411.c +++ b/drivers/media/dvb/frontends/s5h1411.c @@ -38,6 +38,7 @@ struct s5h1411_state { struct dvb_frontend frontend; fe_modulation_t current_modulation; + unsigned int first_tune:1; u32 current_frequency; int if_freq; @@ -489,6 +490,12 @@ static int s5h1411_enable_modulation(struct dvb_frontend *fe, dprintk("%s(0x%08x)\n", __func__, m); + if ((state->first_tune == 0) && (m == state->current_modulation)) { + dprintk("%s() Already at desired modulation. Skipping...\n", + __func__); + return 0; + } + switch (m) { case VSB_8: dprintk("%s() VSB_8\n", __func__); @@ -513,6 +520,7 @@ static int s5h1411_enable_modulation(struct dvb_frontend *fe, } state->current_modulation = m; + state->first_tune = 0; s5h1411_softreset(fe); return 0; @@ -622,6 +630,11 @@ static int s5h1411_init(struct dvb_frontend *fe) /* The datasheet says that after initialisation, VSB is default */ state->current_modulation = VSB_8; + /* Although the datasheet says it's in VSB, empirical evidence + shows problems getting lock on the first tuning request. Make + sure we call enable_modulation the first time around */ + state->first_tune = 1; + if (state->config->output_mode == S5H1411_SERIAL_OUTPUT) /* Serial */ s5h1411_set_serialmode(fe, 1); -- cgit v1.2.3