| Message ID | 974065921c41fa0c97700196de1d921c95fafaaf.1592419750.git.mchehab+huawei@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | [RFC,1/4] media: atomisp: fix identation at I2C Kconfig menu | expand |
Em Thu, 18 Jun 2020 11:50:54 +0200 Marc Gonzalez <marc.w.gonzalez@free.fr> escreveu: > 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+huawei@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. I double-checked this patch. What happens is that there are 3 types of DVB devices: 1. Devices where the Zigzag happens at the hardware level, automatically (DVBFE_ALGO_HW). All they need is to call fe->ops.tune() logic once; 2. Devices that have their own hardware-assisted zigzag logic. Those are handled via DVBFE_ALGO_CUSTOM logic. Those use an special callback: fe->ops.search(fe). 3. Devices that require the Kernel to do zigzag (DVBFE_ALGO_SW). Those should set max_drift and other fields, in order to setup the zigzag steps. In other words, a device driver which uses DVBFE_ALGO_SW should provide the vars that are needed for the zigzag to work, as otherwise, the software zigzag would be just wasting time, as it won't be different than a device driver using DVBFE_ALGO_HW. What the above patch does is to generate a warning when DVBFE_ALGO_SW is used without setting the frequency shift, which is an uAPI/kAPI violation. On such cases, it will fallback to DVBFE_ALGO_HW. The main issue is that testing this patch is not trivial. As you pointed, it can cause regressions. So, instead of this patch, I'll merge one that will just print a warning. We need to fix the frontend drivers case by case. Thanks, Mauro
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"); + + /* fall through */ + case DVBFE_ALGO_HW: + dev_dbg(fe->dvb->device, "%s: Frontend ALGO = DVBFE_ALGO_HW\n", __func__); + + 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; + } + + 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_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; + } + /* Case where we are going to search for a carrier + * User asked us to retune again for some reason, possibly + * requesting a search with a new set of parameters + */ + if (fepriv->algo_status & DVBFE_ALGO_SEARCH_AGAIN) { + if (fe->ops.search) { + fepriv->algo_status = fe->ops.search(fe); + /* We did do a search as was requested, the flags are + * now unset as well and has the flags wrt to search. + */ + } else { + fepriv->algo_status &= ~DVBFE_ALGO_SEARCH_AGAIN; } - /* Case where we are going to search for a carrier - * User asked us to retune again for some reason, possibly - * requesting a search with a new set of parameters - */ - if (fepriv->algo_status & DVBFE_ALGO_SEARCH_AGAIN) { - if (fe->ops.search) { - fepriv->algo_status = fe->ops.search(fe); - /* We did do a search as was requested, the flags are - * now unset as well and has the flags wrt to search. - */ - } else { - fepriv->algo_status &= ~DVBFE_ALGO_SEARCH_AGAIN; - } - } - /* Track the carrier if the search was successful */ - if (fepriv->algo_status != DVBFE_ALGO_SEARCH_SUCCESS) { + } + /* Track the carrier if the search was successful */ + if (fepriv->algo_status != DVBFE_ALGO_SEARCH_SUCCESS) { + fepriv->algo_status |= DVBFE_ALGO_SEARCH_AGAIN; + fepriv->delay = HZ / 2; + } + dtv_property_legacy_params_sync(fe, c, &fepriv->parameters_out); + fe->ops.read_status(fe, &s); + if (s != fepriv->status) { + dvb_frontend_add_event(fe, s); /* update event list */ + fepriv->status = s; + if (!(s & FE_HAS_LOCK)) { + fepriv->delay = HZ / 10; fepriv->algo_status |= DVBFE_ALGO_SEARCH_AGAIN; - fepriv->delay = HZ / 2; + } else { + fepriv->delay = 60 * HZ; } - dtv_property_legacy_params_sync(fe, c, &fepriv->parameters_out); - fe->ops.read_status(fe, &s); - if (s != fepriv->status) { - dvb_frontend_add_event(fe, s); /* update event list */ - fepriv->status = s; - if (!(s & FE_HAS_LOCK)) { - fepriv->delay = HZ / 10; - fepriv->algo_status |= DVBFE_ALGO_SEARCH_AGAIN; - } else { - fepriv->delay = 60 * HZ; - } - } - break; - default: - dev_dbg(fe->dvb->device, "%s: UNDEFINED ALGO !\n", __func__); - break; } - } else { - dvb_frontend_swzigzag(fe); + break; + default: + dev_dbg(fe->dvb->device, "%s: UNDEFINED ALGO !\n", __func__); + break; } }
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. So, add a warning when this happens, and fall back to the single-shot mode. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> --- drivers/media/dvb-core/dvb_frontend.c | 141 +++++++++++++++----------- 1 file changed, 79 insertions(+), 62 deletions(-)