Re: [PATCH] [media] ngene: fix dvb_pll_attach failure

[Antti Palosaari <crope@iki.fi>]

On 12/14/2012 07:28 PM, Patrice Chotard wrote:
> Before dvb_pll_attch call, be sure that drxd demodulator was
> initialized, otherwise, dvb_pll_attach() will always failed.
>
> In dvb_pll_attach(), first thing done is to enable the I2C gate
> control in order to probe the pll by performing a read access.
> As demodulator was not initialized, every i2c access failed.
>
> Reported-by: frederic.mantegazza@gbiloba.org
> Signed-off-by: Patrice Chotard <patricechotard@free.fr>
> ---
>   drivers/media/pci/ngene/ngene-cards.c |    2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/drivers/media/pci/ngene/ngene-cards.c
> b/drivers/media/pci/ngene/ngene-cards.c
> index 96a13ed..e2192db 100644
> --- a/drivers/media/pci/ngene/ngene-cards.c
> +++ b/drivers/media/pci/ngene/ngene-cards.c
> @@ -328,6 +328,8 @@ static int demod_attach_drxd(struct ngene_channel *chan)
>   		return -ENODEV;
>   	}
>
> +	/* initialized the DRXD demodulator */
> +	chan->fe->ops.init(chan->fe);
>   	if (!dvb_attach(dvb_pll_attach, chan->fe, feconf->pll_address,
>   			&chan->i2c_adapter,
>   			feconf->pll_type)) {
>

I don't like that as this causes again more deviation against normal 
procedures. If gate open is needed (for probe or id check?) then 
pll/tuner attach should open it. If that is not easily possible then 
calling gate_control() before pll attach is allowed. init() is very, 
very, bad as generally starts whole chip => starts eating power etc.


Even better would be to let whole gate-control to responsibility of 
DVB-core, but unfortunately current situation is quite mess. Gate is 
operated sometimes by DVB-core (like for init/sleep) and for some cases 
it is left for responsibility of tuner driver. So on real life there is 
mixed solutions and  for init/sleep gate is even double controlled.


regards
Antti

-- 
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