[PATCH] Revert most of 15cc2bb [media] DVB: dtv_property_cache_submit shouldn't modifiy the cache

[Lawrence Rust <lawrence@softsystem.co.uk>]

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 <lvr@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