Em Fri, 5 Sep 2014 23:51:05 -0300 Mauro Carvalho Chehab <m.chehab@xxxxxxxxxxx> escreveu: > Em Sat, 06 Sep 2014 05:09:55 +0300 > Antti Palosaari <crope@xxxxxx> escreveu: > > > Moro! > > > > On 08/29/2014 01:45 PM, Akihiro TSUKADA wrote: > > > moikka, > > > > > >> Start polling thread, which polls once per 2 sec or so, which reads RSSI > > >> and writes value to struct dtv_frontend_properties. That it is, in my > > >> understanding. Same for all those DVBv5 stats. Mauro knows better as he > > >> designed that functionality. > > > > > > I understand that RSSI property should be set directly in the tuner driver, > > > but I'm afraid that creating a kthread just for updating RSSI would be > > > overkill and complicate matters. > > > > > > Would you give me an advice? >> Mauro > > > > Now I know that as I implement it. I added kthread and it works > > correctly, just I though it is aimed to work. In my case signal strength > > is reported by demod, not tuner, because there is some logic in firmware > > to calculate it. > > > > Here is patches you would like to look as a example: > > > > af9033: implement DVBv5 statistic for signal strength > > https://patchwork.linuxtv.org/patch/25748/ > > Actually, you don't need to add a separate kthread to collect the stats. > The DVB frontend core already has a thread that calls the frontend status > on every 3 seconds (the time can actually be different, depending on > the value for fepriv->delay. So, if the device doesn't have any issues > on getting stats on this period, it could just hook the DVBv5 stats logic > at ops.read_status(). In time: not implementing its own thread has one drawback: the driver needs to check if the minimal time needed to get a new stats were already archived. Please see the mt86a20s driver and check for some examples on how to properly do that. There, we do things like: static int mb86a20s_read_signal_strength(struct dvb_frontend *fe) { struct mb86a20s_state *state = fe->demodulator_priv; struct dtv_frontend_properties *c = &fe->dtv_property_cache; int rc; unsigned rf_max, rf_min, rf; if (state->get_strength_time && (!time_after(jiffies, state->get_strength_time))) return c->strength.stat[0].uvalue; To prevent the stats to be called too fast. Regards, Mauro -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
