On 17/06/2020 20:52, Mauro Carvalho Chehab wrote:
> For the zigzag to work, the core needs to have a frequency
> shift. Without that, the zigzag code will just try re-tuning
> several times at the very same frequency, with seems wrong.
s/with/which
Suggest: "the core requires a frequency shift value"
> So, add a warning when this happens, and fall back to the
> single-shot mode.
>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+hua...@kernel.org>
> ---
> drivers/media/dvb-core/dvb_frontend.c | 141 +++++++++++++++-----------
> 1 file changed, 79 insertions(+), 62 deletions(-)
It's hard to discern in the diff what is just white-space adjustment
from one less tab, and what is new code that requires more scrutiny.
I'll try applying the patch, and then diff -w.
Yes, that's much better.
> diff --git a/drivers/media/dvb-core/dvb_frontend.c
> b/drivers/media/dvb-core/dvb_frontend.c
> index ed85dc2a9183..cb577924121e 100644
> --- a/drivers/media/dvb-core/dvb_frontend.c
> +++ b/drivers/media/dvb-core/dvb_frontend.c
> @@ -642,6 +642,9 @@ static void dvb_frontend_wakeup(struct dvb_frontend *fe)
> wake_up_interruptible(&fepriv->wait_queue);
> }
>
> +static u32 dvb_frontend_get_stepsize(struct dvb_frontend *fe);
> +static void prepare_tuning_algo_parameters(struct dvb_frontend *fe);
> +
> static int dvb_frontend_thread(void *data)
> {
> struct dvb_frontend *fe = data;
> @@ -696,78 +699,92 @@ static int dvb_frontend_thread(void *data)
> fepriv->reinitialise = 0;
> }
>
> - /* do an iteration of the tuning loop */
> - if (fe->ops.get_frontend_algo) {
> + if (fe->ops.get_frontend_algo)
> algo = fe->ops.get_frontend_algo(fe);
> - switch (algo) {
> - case DVBFE_ALGO_HW:
> - dev_dbg(fe->dvb->device, "%s: Frontend ALGO =
> DVBFE_ALGO_HW\n", __func__);
> + else
> + algo = DVBFE_ALGO_SW;
>
> - if (fepriv->state & FESTATE_RETUNE) {
> - dev_dbg(fe->dvb->device, "%s: Retune
> requested, FESTATE_RETUNE\n", __func__);
> - re_tune = true;
> - fepriv->state = FESTATE_TUNED;
> - } else {
> - re_tune = false;
> - }
> + /* do an iteration of the tuning loop */
> + switch (algo) {
> + case DVBFE_ALGO_SW:
> + prepare_tuning_algo_parameters(fe);
>
> - if (fe->ops.tune)
> - fe->ops.tune(fe, re_tune,
> fepriv->tune_mode_flags, &fepriv->delay, &s);
> -
> - if (s != fepriv->status &&
> !(fepriv->tune_mode_flags & FE_TUNE_MODE_ONESHOT)) {
> - dev_dbg(fe->dvb->device, "%s: state
> changed, adding current state\n", __func__);
> - dvb_frontend_add_event(fe, s);
> - fepriv->status = s;
> - }
> - break;
> - case DVBFE_ALGO_SW:
> + if (fepriv->max_drift) {
> dev_dbg(fe->dvb->device, "%s: Frontend ALGO =
> DVBFE_ALGO_SW\n", __func__);
> dvb_frontend_swzigzag(fe);
> break;
> - case DVBFE_ALGO_CUSTOM:
> - dev_dbg(fe->dvb->device, "%s: Frontend ALGO =
> DVBFE_ALGO_CUSTOM, state=%d\n", __func__, fepriv->state);
> - if (fepriv->state & FESTATE_RETUNE) {
> - dev_dbg(fe->dvb->device, "%s: Retune
> requested, FESTAT_RETUNE\n", __func__);
> - fepriv->state = FESTATE_TUNED;
> + }
> +
> + /*
> + * See prepare_tuning_algo_parameters():
> + * - Some standards may not use zigzag.
> + */
> + if (!dvb_frontend_get_stepsize(fe))
> + dev_warn(fe->dvb->device,
> + "disabling sigzag, as frontend doesn't
> set frequency step size\n");
s/sigzag/zigzag
I don't understand why you're calling dvb_frontend_get_stepsize() again?
prepare_tuning_algo_parameters() already tried its best to set fepriv->step_size
Why not just:
if (fepriv->max_drift)
do the zigzag
else
warn that zigzag is disabled
> +
> + /* fall through */
Why would you want to fall through from DVBFE_ALGO_SW to DVBFE_ALGO_HW?
I think this changes the behavior before the patch.
