V4L/DVB (9315): s5h1411: Skip reconfiguring demod modulation if already at the desired modulation (50eac6bc) · Commits · 戴 / test

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>

drivers/media/dvb/frontends/s5h1411.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -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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