Re: [PATCH] ts2020: call get_rf_strength from frontend

[Malcolm Priestley <tvboxspy@gmail.com>]

On Sun, 2013-01-06 at 15:37 +0200, Antti Palosaari wrote:
> On 01/06/2013 02:40 PM, Malcolm Priestley wrote:
> > Restore ds3000.c read_signal_strength.
> >
> > Call tuner get_rf_strength from frontend read_signal_strength.
> >
> > We are able to do a NULL check and doesn't limit the tuner
> > attach to the frontend attach area.
> >
> > At the moment the lmedm04 tuner attach is stuck in frontend
> > attach area.
> 
> I would like to nack that, as I see some problems:
> 1) it changes deviation against normal procedures
> 2) interface driver (usb/pci) should have full control to make decision
> 3) you shoot to our own leg easily in power management
> 
This patch does not do any operational changes, and is a proper way to
call to another module with a run time NULL check. The same way as
another tuner function from demodulator is called.

> * actually bug 3) already happened some drivers, like rtl28xxu. Tuner is 
> behind demod and demod is put sleep => no access to tuner. FE callback 
> is overridden (just like you are trying to do as default) which means 
> user-space could still make queries => I/O errors.

In such cases, the tuner init/sleep should also be called.


Regards


Malcolm


> Antti
> 
> 
> >
> > Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
> > ---
> >   drivers/media/dvb-frontends/ds3000.c    | 10 ++++++++++
> >   drivers/media/dvb-frontends/m88rs2000.c |  4 +++-
> >   drivers/media/dvb-frontends/ts2020.c    |  1 -
> >   3 files changed, 13 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/media/dvb-frontends/ds3000.c b/drivers/media/dvb-frontends/ds3000.c
> > index d128f85..1e344b0 100644
> > --- a/drivers/media/dvb-frontends/ds3000.c
> > +++ b/drivers/media/dvb-frontends/ds3000.c
> > @@ -533,6 +533,15 @@ static int ds3000_read_ber(struct dvb_frontend *fe, u32* ber)
> >   	return 0;
> >   }
> >
> > +static int ds3000_read_signal_strength(struct dvb_frontend *fe,
> > +						u16 *signal_strength)
> > +{
> > +	if (fe->ops.tuner_ops.get_rf_strength)
> > +		fe->ops.tuner_ops.get_rf_strength(fe, signal_strength);
> > +
> > +	return 0;
> > +}
> > +
> >   /* calculate DS3000 snr value in dB */
> >   static int ds3000_read_snr(struct dvb_frontend *fe, u16 *snr)
> >   {
> > @@ -1102,6 +1111,7 @@ static struct dvb_frontend_ops ds3000_ops = {
> >   	.i2c_gate_ctrl = ds3000_i2c_gate_ctrl,
> >   	.read_status = ds3000_read_status,
> >   	.read_ber = ds3000_read_ber,
> > +	.read_signal_strength = ds3000_read_signal_strength,
> >   	.read_snr = ds3000_read_snr,
> >   	.read_ucblocks = ds3000_read_ucblocks,
> >   	.set_voltage = ds3000_set_voltage,
> > diff --git a/drivers/media/dvb-frontends/m88rs2000.c b/drivers/media/dvb-frontends/m88rs2000.c
> > index 283c90f..4da5272 100644
> > --- a/drivers/media/dvb-frontends/m88rs2000.c
> > +++ b/drivers/media/dvb-frontends/m88rs2000.c
> > @@ -446,7 +446,9 @@ static int m88rs2000_read_ber(struct dvb_frontend *fe, u32 *ber)
> >   static int m88rs2000_read_signal_strength(struct dvb_frontend *fe,
> >   	u16 *strength)
> >   {
> > -	*strength = 0;
> > +	if (fe->ops.tuner_ops.get_rf_strength)
> > +		fe->ops.tuner_ops.get_rf_strength(fe, strength);
> > +
> >   	return 0;
> >   }
> >
> > diff --git a/drivers/media/dvb-frontends/ts2020.c b/drivers/media/dvb-frontends/ts2020.c
> > index f50e237..ad7ad85 100644
> > --- a/drivers/media/dvb-frontends/ts2020.c
> > +++ b/drivers/media/dvb-frontends/ts2020.c
> > @@ -363,7 +363,6 @@ struct dvb_frontend *ts2020_attach(struct dvb_frontend *fe,
> >
> >   	memcpy(&fe->ops.tuner_ops, &ts2020_tuner_ops,
> >   				sizeof(struct dvb_tuner_ops));
> > -	fe->ops.read_signal_strength = fe->ops.tuner_ops.get_rf_strength;
> >
> >   	return fe;
> >   }
> >
> 
>