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| author | Devin Heitmueller <devin.heitmueller@gmail.com> | 2008-10-20 10:19:07 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2008-10-21 14:31:04 -0200 |
| commit | 50eac6bc466f69e1ecb3a1b64346ed7b979547ac (patch) | |
| tree | 4f91152df4e8713c5b628bedde28c0ca0272a714 /drivers/media/dvb/frontends/s5h1411.c | |
| parent | f0d041e50bc6c8a677922d72b010f80af9b23b18 (diff) | |
| download | linux-50eac6bc466f69e1ecb3a1b64346ed7b979547ac.tar.gz linux-50eac6bc466f69e1ecb3a1b64346ed7b979547ac.tar.bz2 linux-50eac6bc466f69e1ecb3a1b64346ed7b979547ac.zip | |
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 <devin.heitmueller@gmail.com>
Reviewed-by: Michael Krufky <mkrufky@linuxtv.org>
Acked-by: Steven Toth <stoth@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/dvb/frontends/s5h1411.c')
| -rw-r--r-- | drivers/media/dvb/frontends/s5h1411.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/media/dvb/frontends/s5h1411.c b/drivers/media/dvb/frontends/s5h1411.c index 40e0fedf381e..b9ac6d35a1eb 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); |