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: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
---
drivers/media/common/tuners/xc5000.c | 26 +++++++++++-----------
drivers/media/dvb/frontends/drxk_hard.c | 7 ++++++
drivers/media/dvb/frontends/tda18271c2dd.c | 32 ++++++++++++++-------------
3 files changed, 37 insertions(+), 28 deletions(-)
diff --git a/drivers/media/common/tuners/xc5000.c b/drivers/media/common/tuners/xc5000.c
index aa1b2e8..88b329c 100644
--- a/drivers/media/common/tuners/xc5000.c
+++ b/drivers/media/common/tuners/xc5000.c
@@ -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;
diff --git a/drivers/media/dvb/frontends/drxk_hard.c b/drivers/media/dvb/frontends/drxk_hard.c
index f6431ef..dc13fd8 100644
--- a/drivers/media/dvb/frontends/drxk_hard.c
+++ b/drivers/media/dvb/frontends/drxk_hard.c
@@ -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);
diff --git a/drivers/media/dvb/frontends/tda18271c2dd.c b/drivers/media/dvb/frontends/tda18271c2dd.c
index 1b1bf20..de544f6 100644
--- a/drivers/media/dvb/frontends/tda18271c2dd.c
+++ b/drivers/media/dvb/frontends/tda18271c2dd.c
@@ -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
--
1.7.7.1
--
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