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.

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;
        }
 }
-- 
1.7.4.1

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