Em 15-08-2012 21:28, Antti Palosaari escreveu:
> Demodulator cannot perform statistic IOCTLs when it is not tuned.
> Return -EAGAIN in such case.
>
> Signed-off-by: Antti Palosaari <crope@xxxxxx>
> ---
> drivers/media/dvb-core/dvb_frontend.c | 34 +++++++++++++++++++++++++---------
> 1 file changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c
> index 2bc80b1..7d079fb 100644
> --- a/drivers/media/dvb-core/dvb_frontend.c
> +++ b/drivers/media/dvb-core/dvb_frontend.c
> @@ -2132,27 +2132,43 @@ static int dvb_frontend_ioctl_legacy(struct file *file,
> err = fe->ops.read_status(fe, status);
> break;
> }
> +
> case FE_READ_BER:
> - if (fe->ops.read_ber)
> - err = fe->ops.read_ber(fe, (__u32*) parg);
> + if (fe->ops.read_ber) {
> + if (fepriv->thread)
> + err = fe->ops.read_ber(fe, (__u32 *) parg);
> + else
> + err = -EAGAIN;
> + }
> break;
>
> case FE_READ_SIGNAL_STRENGTH:
> - if (fe->ops.read_signal_strength)
> - err = fe->ops.read_signal_strength(fe, (__u16*) parg);
> + if (fe->ops.read_signal_strength) {
> + if (fepriv->thread)
> + err = fe->ops.read_signal_strength(fe, (__u16 *) parg);
> + else
> + err = -EAGAIN;
> + }
> break;
This one doesn't look right, as the frontend can be able to get the signal strength
at the analog part (afaik, most DVB-S frontends do that). Also, some drivers just
map it to the tuner RF strength.
The proper approach for it is to break signal strength into two different statistics:
- analog RF strength;
- signal strength at the demod, after having demod locked.
It makes sense to return -EAGAIN for the second case, but doing it for the first case
is bad, as the RF strength can be used on DVB-S devices, in order to fine-adjust the
antenna position.
Regards,
Mauro.
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