diff options
| author | Mauro Carvalho Chehab <mchehab@redhat.com> | 2011-12-17 20:36:57 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2011-12-20 11:50:23 -0200 |
| commit | fd66c45dd51000ff444231a94ac15ccab8cffd3d (patch) | |
| tree | 9f54f08e52b38c936329a85a396abd98369be048 /drivers/media/dvb/dvb-core/dvb_frontend.c | |
| parent | 669a4ba44d6054f147ef123b0c9a640e49c518e0 (diff) | |
[media] Remove Annex A/C selection via roll-off factor
Instead of using a roll-off factor, change DRX-K & friends to select
the bandwidth filter and the Nyquist half roll-off via delivery system.
This provides a cleaner support for Annex A/C switch.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/dvb/dvb-core/dvb_frontend.c')
| -rw-r--r-- | drivers/media/dvb/dvb-core/dvb_frontend.c | 25 |
1 files changed, 21 insertions, 4 deletions
diff --git a/drivers/media/dvb/dvb-core/dvb_frontend.c b/drivers/media/dvb/dvb-core/dvb_frontend.c index 821b2250ec7..66537b10132 100644 --- a/drivers/media/dvb/dvb-core/dvb_frontend.c +++ b/drivers/media/dvb/dvb-core/dvb_frontend.c @@ -1011,7 +1011,7 @@ static void dtv_property_dump(struct dtv_property *tvp) static int is_legacy_delivery_system(fe_delivery_system_t s) { - if((s == SYS_UNDEFINED) || (s == SYS_DVBC_ANNEX_AC) || + if((s == SYS_UNDEFINED) || (s == SYS_DVBC_ANNEX_A) || (s == SYS_DVBC_ANNEX_B) || (s == SYS_DVBT) || (s == SYS_DVBS) || (s == SYS_ATSC)) return 1; @@ -1032,8 +1032,7 @@ static void dtv_property_cache_init(struct dvb_frontend *fe, c->delivery_system = SYS_DVBS; break; case FE_QAM: - c->delivery_system = SYS_DVBC_ANNEX_AC; - c->rolloff = ROLLOFF_15; /* implied for Annex A */ + c->delivery_system = SYS_DVBC_ANNEX_A; break; case FE_OFDM: c->delivery_system = SYS_DVBT; @@ -1144,9 +1143,10 @@ static void dtv_property_legacy_params_sync(struct dvb_frontend *fe) */ static void dtv_property_adv_params_sync(struct dvb_frontend *fe) { - const struct dtv_frontend_properties *c = &fe->dtv_property_cache; + struct dtv_frontend_properties *c = &fe->dtv_property_cache; struct dvb_frontend_private *fepriv = fe->frontend_priv; struct dvb_frontend_parameters *p = &fepriv->parameters_in; + u32 rolloff = 0; p->frequency = c->frequency; p->inversion = c->inversion; @@ -1178,6 +1178,23 @@ static void dtv_property_adv_params_sync(struct dvb_frontend *fe) else p->u.ofdm.bandwidth = BANDWIDTH_AUTO; } + + /* + * On DVB-C, the bandwidth is a function of roll-off and symbol rate. + * The bandwidth is required for DVB-C tuners, in order to avoid + * inter-channel noise. Instead of estimating the minimal required + * bandwidth on every single driver, calculates it here and fills + * it at the cache bandwidth parameter. + * While not officially supported, a side effect of handling it at + * the cache level is that a program could retrieve the bandwidth + * via DTV_BANDWIDTH_HZ, wich may be useful for test programs. + */ + if (c->delivery_system == SYS_DVBC_ANNEX_A) + rolloff = 115; + if (c->delivery_system == SYS_DVBC_ANNEX_C) + rolloff = 113; + if (rolloff) + c->bandwidth_hz = (c->symbol_rate * rolloff) / 100; } static void dtv_property_cache_submit(struct dvb_frontend *fe) |