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authorDevin Heitmueller <devin.heitmueller@gmail.com>2008-10-20 10:19:07 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2008-10-21 14:31:04 -0200
commit50eac6bc466f69e1ecb3a1b64346ed7b979547ac (patch)
tree4f91152df4e8713c5b628bedde28c0ca0272a714 /drivers/media
parentf0d041e50bc6c8a677922d72b010f80af9b23b18 (diff)
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')
-rw-r--r--drivers/media/dvb/frontends/s5h1411.c13
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);

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