[media] dvb_frontend: improve documentation on set_delivery_system()
While this patch change some things, the updated fields there are used just on printk, so it shouldn't cause any functional changes. Yet, this routine is a little complex, so explain a little more how it works. Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
parent
9474c5e63f
commit
37fa53c6a1
1 changed files with 18 additions and 9 deletions
|
@ -1440,9 +1440,13 @@ static int set_delivery_system(struct dvb_frontend *fe, u32 desired_system)
|
|||
if (desired_system == SYS_UNDEFINED) {
|
||||
/*
|
||||
* A DVBv3 call doesn't know what's the desired system.
|
||||
* So, don't change the current delivery system. Instead,
|
||||
* find the closest DVBv3 system that matches the delivery
|
||||
* system.
|
||||
* Also, DVBv3 applications don't know that ops.info->type
|
||||
* could be changed, and they simply dies when it doesn't
|
||||
* match.
|
||||
* So, don't change the current delivery system, as it
|
||||
* may be trying to do the wrong thing, like setting an
|
||||
* ISDB-T frontend as DVB-T. Instead, find the closest
|
||||
* DVBv3 system that matches the delivery system.
|
||||
*/
|
||||
if (is_dvbv3_delsys(c->delivery_system)) {
|
||||
dprintk("%s() Using delivery system to %d\n",
|
||||
|
@ -1452,27 +1456,29 @@ static int set_delivery_system(struct dvb_frontend *fe, u32 desired_system)
|
|||
type = dvbv3_type(c->delivery_system);
|
||||
switch (type) {
|
||||
case DVBV3_QPSK:
|
||||
desired_system = FE_QPSK;
|
||||
desired_system = SYS_DVBS;
|
||||
break;
|
||||
case DVBV3_QAM:
|
||||
desired_system = FE_QAM;
|
||||
desired_system = SYS_DVBC_ANNEX_A;
|
||||
break;
|
||||
case DVBV3_ATSC:
|
||||
desired_system = FE_ATSC;
|
||||
desired_system = SYS_ATSC;
|
||||
break;
|
||||
case DVBV3_OFDM:
|
||||
desired_system = FE_OFDM;
|
||||
desired_system = SYS_DVBT;
|
||||
break;
|
||||
default:
|
||||
dprintk("%s(): This frontend doesn't support DVBv3 calls\n",
|
||||
__func__);
|
||||
return -EINVAL;
|
||||
}
|
||||
delsys = c->delivery_system;
|
||||
} else {
|
||||
/*
|
||||
* Check if the desired delivery system is supported
|
||||
* This is a DVBv5 call. So, it likely knows the supported
|
||||
* delivery systems.
|
||||
*/
|
||||
|
||||
/* Check if the desired delivery system is supported */
|
||||
ncaps = 0;
|
||||
while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {
|
||||
if (fe->ops.delsys[ncaps] == desired_system) {
|
||||
|
@ -1518,6 +1524,9 @@ static int set_delivery_system(struct dvb_frontend *fe, u32 desired_system)
|
|||
}
|
||||
|
||||
/*
|
||||
* The DVBv3 or DVBv5 call is requesting a different system. So,
|
||||
* emulation is needed.
|
||||
*
|
||||
* Emulate newer delivery systems like ISDBT, DVBT and DMBTH
|
||||
* for older DVBv5 applications. The emulation will try to use
|
||||
* the auto mode for most things, and will assume that the desired
|
||||
|
|
Loading…
Reference in a new issue