Em 21-11-2011 22:04, Andreas Oberritter escreveu:
> On 21.11.2011 22:06, Manu Abraham wrote:
>>
>> 0004-TDA18271-Allow-frontend-to-set-DELSYS-rather-than-qu.patch
>>
>>
>> From 2ece38602678ae323450d0e35379147e6e086326 Mon Sep 17 00:00:00 2001
>> From: Manu Abraham <abraham.manu@xxxxxxxxx>
>> Date: Sat, 19 Nov 2011 19:50:09 +0530
>> Subject: [PATCH 04/13] TDA18271: Allow frontend to set DELSYS, rather than querying fe->ops.info.type
>>
>> With any tuner that can tune to multiple delivery systems/standards, it does
>> query fe->ops.info.type to determine frontend type and set the delivery
>> system type. fe->ops.info.type can handle only 4 delivery systems, viz FE_QPSK,
>> FE_QAM, FE_OFDM and FE_ATSC.
>>
>> The change allows the tuner to be set to any delivery system specified in
>> fe_delivery_system_t, thereby simplifying a lot of issues.
>>
>> Signed-off-by: Manu Abraham <abraham.manu@xxxxxxxxx>
>> ---
>> drivers/media/common/tuners/tda18271-fe.c | 80 +++++++++++++++++++++++++++
>> drivers/media/common/tuners/tda18271-priv.h | 2 +
>> 2 files changed, 82 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/media/common/tuners/tda18271-fe.c b/drivers/media/common/tuners/tda18271-fe.c
>> index 3347c5b..6e29faf 100644
>> --- a/drivers/media/common/tuners/tda18271-fe.c
>> +++ b/drivers/media/common/tuners/tda18271-fe.c
>> @@ -928,6 +928,85 @@ fail:
>>
>> /* ------------------------------------------------------------------ */
>>
>> +static int tda18271_set_state(struct dvb_frontend *fe,
>> + enum tuner_param param,
>> + struct tuner_state *state)
>> +{
>> + struct tda18271_priv *priv = fe->tuner_priv;
>> + struct tuner_state *req = &priv->request;
>> + struct tda18271_std_map *std_map = &priv->std;
>> + struct tda18271_std_map_item *map;
>> + int ret;
>> +
>> + BUG_ON(!priv);
>
> At this point priv has already been dereferenced.
>
>> + if (param & DVBFE_TUNER_DELSYS)
>> + req->delsys = state->delsys;
>> + if (param & DVBFE_TUNER_FREQUENCY)
>> + req->frequency = state->frequency;
>> + if (param & DVBFE_TUNER_BANDWIDTH)
>> + req->bandwidth = state->bandwidth;
>
> What happens if one of these flags is not set, when the function is
> called for the first time? priv->request doesn't seem to get initialized.
>
> Regards,
> Andreas
>
>> +
>> + priv->mode = TDA18271_DIGITAL;
>> +
>> + switch (req->delsys) {
>> + case SYS_ATSC:
>> + map = &std_map->atsc_6;
>> + req->bandwidth = 6000000;
>> + break;
>> + case SYS_DVBC_ANNEX_B:
>> + map = &std_map->qam_6;
>> + req->bandwidth = 6000000;
>> + break;
>> + case SYS_DVBT:
>> + case SYS_DVBT2:
>> + switch (req->bandwidth) {
>> + case 6000000:
>> + map = &std_map->dvbt_6;
>> + break;
>> + case 7000000:
>> + map = &std_map->dvbt_7;
>> + break;
>> + case 8000000:
>> + map = &std_map->dvbt_8;
>> + break;
>> + default:
>> + ret = -EINVAL;
>> + goto fail;
>> + }
>> + break;
>> + case SYS_DVBC_ANNEX_AC:
>> + map = &std_map->qam_8;
>> + req->bandwidth = 8000000;
>> + break;
This premise is not correct, and causes tuning failure on places where
channels are spaced with 6MHz.
The bandwidth should be calculated as a function of the rolloff and symbol
rate. I had to fix it on a few places, for devices to work with Net Digital
Cable operator in Brazil (6MHz spaced channels, 5.217 KBauds per carrier,
DVB-C Annex A).
The correct way for doing it is:
else if (fe->ops.info.type == FE_QAM) {
/*
* 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;
(from drivers/media/dvb/frontends/tda18271c2dd.c)
Where ROLLOFF_13 is used on Annex C, and ROLLOF_15 on Annex A.
The same fix should be applied to all DVB-C capable tuners. Alternatively, we
should put some ancillary function at the core, and let the core estimate the
needed bandwidth for DVB-C.
PS.: While I didn't test, I suspect that places using 7MHz-spaced channels will
also increase the reception, as less inter-channel noise will be sent to
the demod.
>> + default:
>> + tda_warn("Invalid delivery system!\n");
>> + ret = -EINVAL;
>> + goto fail;
>> + }
>> + tda_dbg("Trying to tune .. delsys=%d modulation=%d frequency=%d bandwidth=%d",
>> + req->delsys,
>> + req->modulation,
>> + req->frequency,
>> + req->bandwidth);
>> +
>> + /* When tuning digital, the analog demod must be tri-stated */
>> + if (fe->ops.analog_ops.standby)
>> + fe->ops.analog_ops.standby(fe);
>> +
>> + ret = tda18271_tune(fe, map, req->frequency, req->bandwidth);
>> +
>> + if (tda_fail(ret))
>> + goto fail;
>> +
>> + priv->if_freq = map->if_freq;
>> + priv->frequency = req->frequency;
>> + priv->bandwidth = (req->delsys == SYS_DVBT || req->delsys == SYS_DVBT2) ?
>> + req->bandwidth : 0;
>> +fail:
>> + return ret;
>> +}
>> +
>> +
>> static int tda18271_set_params(struct dvb_frontend *fe,
>> struct dvb_frontend_parameters *params)
>> {
>> @@ -1249,6 +1328,7 @@ static const struct dvb_tuner_ops tda18271_tuner_ops = {
>> .init = tda18271_init,
>> .sleep = tda18271_sleep,
>> .set_params = tda18271_set_params,
>> + .set_state = tda18271_set_state,
>> .set_analog_params = tda18271_set_analog_params,
>> .release = tda18271_release,
>> .set_config = tda18271_set_config,
>> diff --git a/drivers/media/common/tuners/tda18271-priv.h b/drivers/media/common/tuners/tda18271-priv.h
>> index 454c152..bd1bf58 100644
>> --- a/drivers/media/common/tuners/tda18271-priv.h
>> +++ b/drivers/media/common/tuners/tda18271-priv.h
>> @@ -126,6 +126,8 @@ struct tda18271_priv {
>>
>> u32 frequency;
>> u32 bandwidth;
>> +
>> + struct tuner_state request;
>> };
>>
>> /*---------------------------------------------------------------------*/
>> -- 1.7.1
>>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-media" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
