On 05.11.2011 16:19, Lawrence Rust wrote:
> Hi,
>
> I believe that I have found a problem with dtv_property_cache updating
> when handling the legacy API. This was introduced between 2.6.39 and
> 3.0.
>
> dtv_property_cache_submit() in dvb_frontend.c tests the field
> delivery_system and if it's a legacy type (including SYS_UNDEFINED) then
> it calls dtv_property_legacy_params_sync().
>
> The original patch removed the assignment to delivery_system in this
> function. However, the legacy API allows delivery_system to be
> SYS_UNDEFINED - in fact is_legacy_delivery_system() tests for this
> value.
>
> If the delivery_system field is left as SYS_UNDEFINED then when tuning
> is started, fe->ops.set_frontend() fails.
>
> The current version of MythTV 0.24.1 is affected by this bug when using
> a dvb-s2 card (tbs6981) tuned to a dvb-s channel.
How does MythTV set the parameters (i.e. using which interface, calls)?
If using S2API, it should also set DTV_DELIVERY_SYSTEM.
SYS_UNDEFINED get's set by dvb_frontend_clear_cache() only. I think it
would be better to call dtv_property_cache_init() from there to get rid
of it.
> Signed-off-by: Lawrence Rust <l...@softsystem.co.uk>
> ---
> drivers/media/dvb/dvb-core/dvb_frontend.c | 9 ++++++++-
> 1 files changed, 8 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/media/dvb/dvb-core/dvb_frontend.c
> b/drivers/media/dvb/dvb-core/dvb_frontend.c
> index 5b6b451..06c3975 100644
> --- a/drivers/media/dvb/dvb-core/dvb_frontend.c
> +++ b/drivers/media/dvb/dvb-core/dvb_frontend.c
> @@ -1076,7 +1076,7 @@ static void dtv_property_cache_sync(struct dvb_frontend
> *fe,
> */
> static void dtv_property_legacy_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;
>
> @@ -1088,12 +1088,14 @@ static void dtv_property_legacy_params_sync(struct
> dvb_frontend *fe)
> dprintk("%s() Preparing QPSK req\n", __func__);
> p->u.qpsk.symbol_rate = c->symbol_rate;
> p->u.qpsk.fec_inner = c->fec_inner;
> + c->delivery_system = SYS_DVBS;
> break;
> case FE_QAM:
> dprintk("%s() Preparing QAM req\n", __func__);
> p->u.qam.symbol_rate = c->symbol_rate;
> p->u.qam.fec_inner = c->fec_inner;
> p->u.qam.modulation = c->modulation;
> + c->delivery_system = SYS_DVBC_ANNEX_AC;
> break;
> case FE_OFDM:
> dprintk("%s() Preparing OFDM req\n", __func__);
> @@ -1111,10 +1113,15 @@ static void dtv_property_legacy_params_sync(struct
> dvb_frontend *fe)
> p->u.ofdm.transmission_mode = c->transmission_mode;
> p->u.ofdm.guard_interval = c->guard_interval;
> p->u.ofdm.hierarchy_information = c->hierarchy;
> + c->delivery_system = SYS_DVBT;
> break;
> case FE_ATSC:
> dprintk("%s() Preparing VSB req\n", __func__);
> p->u.vsb.modulation = c->modulation;
> + if ((c->modulation == VSB_8) || (c->modulation == VSB_16))
> + c->delivery_system = SYS_ATSC;
> + else
> + c->delivery_system = SYS_DVBC_ANNEX_B;
> break;
> }
> }
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