Commit 2440f7af authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab
Browse files

[media] Properly implement ITU-T J.88 Annex C support 



The Annex C support were broken with the previous implementation,
as, at xc5000 and tda18271c2dd, it were choosing the wrong bandwidth
for some symbol rates.

At DRX-J, it were always selecting Annex A, even having Annex C
support coded there.

Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 39ce61a8

drivers/media/common/tuners/xc5000.c

+13 −13
Original line number Diff line number Diff line
@@ -628,20 +628,12 @@ static void xc_debug_dump(struct xc5000_priv *priv) 
	dprintk(1, "*** Quality (0:<8dB, 7:>56dB) = %d\n", quality);

}



/*

 * As defined on EN 300 429, the DVB-C roll-off factor is 0.15.

 * So, the amount of the needed bandwith is given by:

 * 	Bw = Symbol_rate * (1 + 0.15)

 * As such, the maximum symbol rate supported by 6 MHz is given by:

 *	max_symbol_rate = 6 MHz / 1.15 = 5217391 Bauds

 */

#define MAX_SYMBOL_RATE_6MHz	5217391



static int xc5000_set_params(struct dvb_frontend *fe,

	struct dvb_frontend_parameters *params)

{

	struct xc5000_priv *priv = fe->tuner_priv;

	int ret;

	u32 bw;



	if (xc5000_is_firmware_loaded(fe) != XC_RESULT_SUCCESS) {

		if (xc_load_fw_and_init_tuner(fe) != XC_RESULT_SUCCESS) {
@@ -707,11 +699,19 @@ static int xc5000_set_params(struct dvb_frontend *fe, 
			dprintk(1, "%s() QAM modulation\n", __func__);

			priv->rf_mode = XC_RF_MODE_CABLE;

			/*

			 * Using a 8MHz bandwidth sometimes fail

			 * with 6MHz-spaced channels, due to inter-carrier

			 * interference. So, use DTV6 firmware

			 * Using a higher bandwidth at the tuner filter may

			 * allow inter-carrier interference.

			 * So, determine the minimal channel spacing, in order

			 * to better adjust the tuner filter.

			 * According with ITU-T J.83, the bandwidth is given by:

			 * bw = Simbol Rate * (1 + roll_off), where the roll_off

			 * is equal to 0.15 for Annex A, and 0.13 for annex C

			 */

			if (params->u.qam.symbol_rate <= MAX_SYMBOL_RATE_6MHz) {

			if (fe->dtv_property_cache.rolloff == ROLLOFF_13)

				bw = (params->u.qam.symbol_rate * 13) / 10;

			else

				bw = (params->u.qam.symbol_rate * 15) / 10;

			if (bw <= 6000000) {

				priv->bandwidth = BANDWIDTH_6_MHZ;

				priv->video_standard = DTV6;

				priv->freq_hz = params->frequency - 1750000;

drivers/media/dvb/frontends/drxk_hard.c

+7 −0
Original line number Diff line number Diff line
@@ -6218,6 +6218,13 @@ static int drxk_set_parameters(struct dvb_frontend *fe, 
		return -EINVAL;

	}



	if (state->m_OperationMode == OM_QAM_ITU_A ||

	    state->m_OperationMode == OM_QAM_ITU_C) {

		if (fe->dtv_property_cache.rolloff == ROLLOFF_13)

			state->m_OperationMode = OM_QAM_ITU_C;

		else

			state->m_OperationMode = OM_QAM_ITU_A;

	}



	if (fe->ops.i2c_gate_ctrl)

		fe->ops.i2c_gate_ctrl(fe, 1);

drivers/media/dvb/frontends/tda18271c2dd.c

+17 −15
Original line number Diff line number Diff line
@@ -1123,20 +1123,6 @@ static int release(struct dvb_frontend *fe) 
	return 0;

}



/*

 * As defined on EN 300 429 Annex A and on ITU-T J.83 annex A, the DVB-C

 * roll-off factor is 0.15.

 * According with the specs, the amount of the needed bandwith is given by:

 *	Bw = Symbol_rate * (1 + 0.15)

 * As such, the maximum symbol rate supported by 6 MHz is

 *	max_symbol_rate = 6 MHz / 1.15 = 5217391 Bauds

 *NOTE: For ITU-T J.83 Annex C, the roll-off factor is 0.13. So:

 *	max_symbol_rate = 6 MHz / 1.13 = 5309735 Baud

 *	That means that an adjustment is needed for Japan,

 *	but, as currently DRX-K is hardcoded to Annex A, let's stick

 *	with 0.15 roll-off factor.

 */

#define MAX_SYMBOL_RATE_6MHz	5217391



static int set_params(struct dvb_frontend *fe,

		      struct dvb_frontend_parameters *params)
@@ -1144,6 +1130,7 @@ static int set_params(struct dvb_frontend *fe, 
	struct tda_state *state = fe->tuner_priv;

	int status = 0;

	int Standard;

	u32 bw;



	state->m_Frequency = params->frequency;
@@ -1161,8 +1148,23 @@ static int set_params(struct dvb_frontend *fe, 
			break;

		}

	else if (fe->ops.info.type == FE_QAM) {

		if (params->u.qam.symbol_rate <= MAX_SYMBOL_RATE_6MHz)

		/*

		 * Using a higher bandwidth at the tuner filter may

		 * allow inter-carrier interference.

		 * So, determine the minimal channel spacing, in order

		 * to better adjust the tuner filter.

		 * According with ITU-T J.83, the bandwidth is given by:

		 * bw = Simbol Rate * (1 + roll_off), where the roll_off

		 * is equal to 0.15 for Annex A, and 0.13 for annex C

		 */

		if (fe->dtv_property_cache.rolloff == ROLLOFF_13)

			bw = (params->u.qam.symbol_rate * 13) / 10;

		else

			bw = (params->u.qam.symbol_rate * 15) / 10;

		if (bw <= 6000000)

			Standard = HF_DVBC_6MHZ;

		else if (bw <= 7000000)

			Standard = HF_DVBC_7MHZ;

		else

			Standard = HF_DVBC_8MHZ;

	} else