[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: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/common/tuners/xc5000.c b/drivers/media/common/tuners/xc5000.c
index aa1b2e8..88b329c 100644 (file)
--- 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 (file)
--- 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 (file)
--- 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