Re: [PATCH 1/6] m88ds3103, montage dvb-s/s2 demodulator driver

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Antti, Mauro,

i believe we're all on the same page here and i just want to summarize
based on all the discussion so far and if we all agree:

1) ds3000 and ts2020 code split, there are already several strong
arguments about it and most of all that it turned out there is
reference design with 3rd party tuner that works both with ds3000 and
stv090x demodulators. i will take care of this task

2) the result of 1) would be that the following DVB-S2 tuner and
demodulator drivers will be able to work in any combination of each
other (assuming there is such hardware design available): stb0899*,
stv090x*, ds3000, stv6110x*, stb6100* and ts2020. that's good, because
it starts to put order, because those are significant part of the
DVB-S2 drivers in the kernel

3) not only, because of 2), but in general it's not clear why there is
stv6110.* driver, which is for the exact same silicone as stv6110x*,
as well stv0900*, which is for the same family of chips as stv090x*. i
can help a little here to the degree that i can make all bridge
drivers depend on stv6110x* and stv090x* except the driver for one
card made by NetUP - there i can just do it in theory, but i can't
test and probably break support for it

4) after 1), 2) and if 3) is resolved the only DVB-S2 drivers that
will continue to be married to one particular tuner (CX24118A) that
will left are cx24116 and tda10071, which for the time being will be
left that way until basically there is someone that volunteers to make
separate CX24118A driver based on the LG, SHARP and Comtech datasheets
that are available in the public domain, for which i gave details in a
previous email, and which in my opinion contain sufficient information
that task to be made

5) ds3103 and ts2022 support, done in form of a patch respectively to
ds3000 driver and ts2020 driver or if ts2022 happens to be very
different than ts2020 then ts2022 support be made as separate driver,
i guess Max will take this

6) if it's necessary bug fixes, improvements, etc to the shared code
between ds3000 and ds3103, but only after review, discussion and
argumentation why those changes are actually needed

On Fri, Apr 27, 2012 at 11:42 PM, Antti Palosaari <crope@xxxxxx> wrote:
> On 27.04.2012 23:21, Konstantin Dimitrov wrote:
>>
>> On Fri, Apr 27, 2012 at 10:55 PM, Antti Palosaari<crope@xxxxxx>  wrote:
>>>
>>> On 27.04.2012 22:01, Konstantin Dimitrov wrote:
>>>>
>>>>
>>>> Mauro, your reasoning makes sense to me. so, let's split them and at
>>>> least settle this part of the discussion - i will do as far as my
>>>> spare time allows, as well make sure there are no some problems
>>>> introduced after the split.
>>>>
>>>> also, in one email i've just sent in answer to Antti there is enough
>>>> argument why such split, i.e. tuner-pass-through-mode is subject to
>>>> discussion about CX24116 and TDA10071 drivers too. currently, majority
>>>> of DVB-S2 demodulator drivers in the kernel are married to particular
>>>> tuners and there is no split.
>>>
>>>
>>>
>>> I read the mail and as it was long study, I comment only that
>>> CX24116+CX24118A and TDA10071+CX24118A demod+tuner combos versus Montage
>>> demod+tuner combos. As you may see, CX24116 and TDA10071 are so much
>>> different than both needs own driver. But as you said those are married
>>> always as a demod+tuner.
>>>
>>> So if I use your logic, what happens if CX24118A tuner is not driven by
>>> CX24116 or TDA10071 firmware? ==>  it happens we have two drivers,
>>> CX24116
>>> and TDA10071 *both* having similar CX24118A tuner driver code inside!
>>> Same
>>> tuner driver code inside two demods drivers. Could you now understand why
>>> we
>>> want it split?
>>> The reason which saves us having CX24118A tuner driver is that it is
>>> inside
>>> both CX24116 and TDA10071 firmware.
>>>
>>> There is mainly two different controlling situation. Most commonly driver
>>> controls chip but in some cases it is firmware which is controlling. And
>>> I
>>> don't see it very important trying always to by-pass firmware control and
>>> use driver for that.
>>>
>>
>> i got that point, but what happens if tomorrow their is CX24116 or
>> TDA10071 design with tuner different than CX14118A? in fact the LG
>> datasheet i pointed out to you clearly states that for example there
>> is actually such design - case when CX24116 is used with CX24128 tuner
>> instead CX24118A in which case the only way is to bypass the firmware
>> and control the tuner directly. also, isn't it even double bad the
>> current state of CX24116 or TDA10071 drivers - from one side they use
>> 2 firmwares, part of which is doing the same, i.e control the CX24118A
>> and from the other side they depend on proprietary firmware to do
>> something that can be done in open-source code? i don't know, but at
>> least from my point of view if that's not worse than the current
>> status of ds3000 driver, it's at least as wrong as it, i.e. there
>> isn't not only separation of tuner and demodulator code in CX24116 or
>> TDA10071 drivers, but there is not even a code that can allow they to
>> be separated easily, because making CX14118A driver from scratch is
>> task that will need some effort. anyway, maybe, it's just me, but i
>> prefer to depend as less as possible on proprietary firmwares done is
>> such way. however, there is no any doubt current CX24116 or TDA10071
>> drivers don't allow any other tuner that is not supported by the
>> proprietary firmware to be used and thus they break the rule of tuner
>> and demodulator code separation. so, i really don't understand what
>> makes CX24116 or TDA10071 drivers different than the others, i.e. why
>> they are developed in such way and there is no discussion about them
>> to be changed in way that allow use of other tuner like CX24128, which
>> is not supported by the proprietary firmwares. so, the only
>> explanation from my perspective is lack of such need in real-life, but
>> it's the same for ds3000.
>
>
> In case of new device having CX24116 or TDA10071, but different tuner than
> firmware controlled CX14118A, driver must be changed to support new
> configuration. Or even make new driver if differences are too big. I suspect
> implementing new .set_frontend() callback is almost everything what is
> needed. Then add configuration option .tuner_controlled_by_firmware or
> something like that. There is likely rather similar existing cases.
>
> IIRC someone mentioned AF9035/AF9033 firmwares have different versions for
> different tuners. Also AF9015 uploads firmware to AF9013 demod, external or
> internal. Still AF9013 driver could upload firmware independently. There is
> many kind of cases chip/firmware can control other chips. And if you look
> AF9015/AF9013 and AF9035/AF9033 drivers you can see some examples of
> splitting drivers even those are many times integrated together. OK, that
> AF90xx stuff goes to DVB-T side but it is good example of splitting drivers
> and supporting very wide set of demod/tuner combinations.
>
> And it is nice you found CX24116 is sold by two different tuners :) If those
> tuners are controlled by the driver we can see similar mess than ds3000 +
> ts2020 or ts2022. At the some point handling different tuner drivers inside
> one demod driver goes difficult - errors can be done easily and maintaining
> goes hard.
>
>
> regards
> Antti
> --
> http://palosaari.fi/
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