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[media] dvb: remove bogus modulation check

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This code is wrong as I should have coded it as SYS_DVBC, instead of
SYS_DVBS & friends. Anyway, this check has other problems

1) it does some "magic" by assuming that all QAM modulations are below
  QAM_AUTO;

2) it checks modulation parameters only for one delivery system.
   Or the core should check invalid parameters for all delivery
   systems, or it should let the frontend drivers do it;

3) frontend drivers should already be checking for invalid parameters
   (most of them do it, anyway);

4) not all modulations are mapped at fe->ops.info.caps, so it is not
   even possible to check for the valid modulations inside the core
   for some delivery systems;

5) The core check is incomplete anyway: it only checks for a few
   parameters. If moved into the core other parameters like bandwidth
   and fec should also be checked;

6) 2nd gen DVB-C uses OFDM. So, that test would fail for it.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Mauro Carvalho Chehab 2012-01-07 05:38:38 -02:00
parent c0fdbd3367
commit b247377ace
1 changed files with 0 additions and 23 deletions
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23
drivers/media/dvb/dvb-core/dvb_frontend.c
View File

@ -897,29 +897,6 @@ static int dvb_frontend_check_parameters(struct dvb_frontend *fe)
break;
}
/*
* check for supported modulation
*
* This is currently hacky. Also, it only works for DVB-S & friends,
* and not all modulations has FE_CAN flags
*/
switch (c->delivery_system) {
case SYS_DVBS:
case SYS_DVBS2:
case SYS_TURBO:
if ((c->modulation > QAM_AUTO ||
!((1 << (c->modulation + 10)) & fe->ops.info.caps))) {
printk(KERN_WARNING
"DVB: adapter %i frontend %i modulation %u not supported\n",
fe->dvb->num, fe->id, c->modulation);
return -EINVAL;
}
break;
default:
/* FIXME: it makes sense to validate othere delsys here */
break;
}
return 0;
}