Em Thu, 5 Jul 2018 10:58:42 +0900
"Katsuhiro Suzuki" <suzuki.katsuhiro@xxxxxxxxxxxxx> escreveu:
> Hi Mauro,
>
> > -----Original Message-----
> > From: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>
> > Sent: Thursday, July 5, 2018 1:58 AM
> > To: Suzuki, Katsuhiro/鈴木 勝博 <suzuki.katsuhiro@xxxxxxxxxxxxx>
> > Cc: linux-media@xxxxxxxxxxxxxxx; Masami Hiramatsu
> <masami.hiramatsu@xxxxxxxxxx>;
> > Jassi Brar <jaswinder.singh@xxxxxxxxxx>; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> > linux-kernel@xxxxxxxxxxxxxxx
> > Subject: Re: [PATCH v3] media: dvb-frontends: add Socionext SC1501A ISDB-S/T
> > demodulator driver
> >
> > Hi Katsuhiro-san,
> >
> > Em Thu, 21 Jun 2018 12:17:48 +0900
> > Katsuhiro Suzuki <suzuki.katsuhiro@xxxxxxxxxxxxx> escreveu:
> >
> > > This patch adds a frontend driver for the Socionext SC1501A series
> > > and Socionext MN88443x ISDB-S/T demodulators.
> >
> > Sorry for taking so long to review it. We're missing a sub-maintainer
> > for DVB, with would otherwise speed up reviews of DVB patches.
>
> No problem, thank you for reviewing! I appreciate it.
>
>
> > >
> > > The maximum and minimum frequency of Socionext SC1501A comes from
> > > ISDB-S and ISDB-T so frequency range is the following:
> > > - ISDB-S (BS/CS110 IF frequency in kHz, Local freq 10.678GHz)
> > > - Min: BS-1: 1032000 => 1032.23MHz
> > > - Max: ND24: 2701000 => 2070.25MHz
> > > - ISDB-T (in Hz)
> > > - Min: ch13: 470000000 => 470.357857MHz
> > > - Max: ch62: 770000000 => 769.927857MHz
> >
> > There is actually an error on that part of the driver. Right now,
> > the DVB core expects Satellite frequencies (DVB-S, ISDB-S, ...)
> > in kHz. For all other delivery systems, it is in Hz.
> >
> > It is this way due to historic reasons. While it won't be hard to
> > change the core, that would require to touch all Satellite drivers.
> >
> > As there are very few frontend drivers that accept both Satellite
> > and Terrestrial standards, what we do, instead, is to setup
> > two frontends. See, for example, drivers/media/dvb-frontends/helene.c.
> >
>
> Thank you for describing it. I understand our device is rare case, and
> the reason why Helene has Terrestrial and Satellite structures.
>
> I'm using MN884434 device that has 2 cores. I want to setup DVB adapter
> devices (/dev/dvb/adapter0/*) for our frontend system as the following:
>
> - adapter0: for core 0, ISDB-T, ISDB-S
> - adapter1: for core 1, ISDB-T, ISDB-S
Yeah, that is what it was supposed to work, if the core was ready for it.
> But it seems one DVB adapter device support only ISDB-T or only ISDB-S
> if I divide structures. So I define the adapters as the following:
>
> - adapter0: for core 0, ISDB-T
> - adapter1: for core 0, ISDB-S
> - adapter2: for core 1, ISDB-T
> - adapter3: for core 1, ISDB-S
>
> Is this correct?
That's the way the current driver with uses helene does.
>
>
> > ...
> > > +static const struct dvb_frontend_ops sc1501a_ops = {
> > > + .delsys = { SYS_ISDBS, SYS_ISDBT },
> > > + .info = {
> > > + .name = "Socionext SC1501A",
> > > + .frequency_min = 1032000,
> > > + .frequency_max = 770000000,
> > > + .caps = FE_CAN_INVERSION_AUTO | FE_CAN_FEC_AUTO |
> > > + FE_CAN_QAM_AUTO | FE_CAN_TRANSMISSION_MODE_AUTO |
> > > + FE_CAN_GUARD_INTERVAL_AUTO | FE_CAN_HIERARCHY_AUTO,
> > > + },
> > > +
> > > + .sleep = sc1501a_sleep,
> > > + .set_frontend = sc1501a_set_frontend,
> > > + .get_tune_settings = sc1501a_get_tune_settings,
> > > + .read_status = sc1501a_read_status,
> > > +};
> >
> > In other words, you'll need to declare two structs here, one for ISDB-T
> > and another one for ISDB-S.
> >
>
> OK, I'm going to divide this structure for Terrestrial and Satellite. And
> add attach functions same as Helene driver.
>
> I'll send v4 patch.
I ended by writing two patches that should be solving the issues
inside the core. With them[1], it will work the way you want.
There is a catch: you'll need to convert Helene to have a single
entry and be sure that the driver that currently uses it (netup_unidvb)
will keep working. I guess I have one such hardware here for testing.
[1] after tested/reviewed - I didn't test them yet. Feel free to test.
So, please look at the two patches I sent today to the mailing list.
(not sure why, they're taking a long time to arrive there - perhaps
vger has some issues).
I added them on this tree:
https://git.linuxtv.org/mchehab/experimental.git/log/?h=dvb_freq_hz
it is the last two patches there:
- https://git.linuxtv.org/mchehab/experimental.git/commit/?h=dvb_freq_hz&id=b3d63a8f038d136b26692bc3a14554960e767f4a
- https://git.linuxtv.org/mchehab/experimental.git/commit/?h=dvb_freq_hz&id=2a369e8faf3b277baff4026371f298e95c84fbb2
I'm not sure if all applications will do the right thing, though, as
it will depend if they query the capabilities before or after switching
to a different delivery system. If it get caps before and store them
in Hz, apps will work, but tests are required.
>
>
> > Yeah, I know that this sucks. If you are in the mood of touching the
> > DVB core, I'm willing to consider a patch that would fix this, provided
> > that it won't break backward compatibility with other drivers (or would
> > convert the other satellite drivers to use the new way).
> >
> > Thanks,
> > Mauro
>
> Hmm, I don't know the details of DVB core, I try to investigate it.
>
>
> Regards,
> --
> Katsuhiro Suzuki
>
>
>
Thanks,
Mauro
