On Mon, Dec 12, 2011 at 9:52 PM, Mauro Carvalho Chehab
<mchehab@xxxxxxxxxx> wrote:
> On 12-12-2011 13:00, Manu Abraham wrote:
>>
>> On Mon, Dec 12, 2011 at 7:26 PM, Mauro Carvalho Chehab
>> <mchehab@xxxxxxxxxx> wrote:
>>>
>>> On 12-12-2011 11:40, Manu Abraham wrote:
>>>>
>>>>
>>>> On Mon, Dec 12, 2011 at 6:49 PM, Mauro Carvalho Chehab
>>>
>>>
>>>
>>>>> This also means that just doing an alias from FE_QAM and
>>>>> SYS_DVBC_ANNEX_AC
>>>>> to
>>>>> SYS_DVBC_ANNEX_A may break something, as, for most devices,
>>>>> SYS_DVBC_ANNEX_AC
>>>>> really means both Annex A and C.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> With the current approach, the application can determine whether
>>>> the hardware supports through the DELSYS enumeration.
>>>>
>>>> So, if you have a device that needs to support both ANNEX_A and
>>>> ANNEX_C, it should be rather doing
>>>>
>>>> case DTV_ENUM_DELSYS:
>>>> buffer.data[0] = SYS_DVBC_ANNEX_A;
>>>> buffer.data[1] = SYS_DVBC_ANNEX_C;
>>>> break;
>>>
>>>
>>>
>>> Sure, but we'll need a logic to handle queries for SYS_DVBC_ANNEX_AC
>>> anyway, if any of the existing DVB-C drivers is currently prepared to
>>> support both.
>>>
>>> I'm not concerned with drx-k. The support for both standards are for
>>> kernel 3.3. So, no backward compatibility is needed here.
>>>
>>> While there is no explicit option, the code for stv0297, stv0367,
>>> tda10021 and tda10023 drivers are not clear if they support both
>>> (maybe roll-off might be auto-detected?) or just SYS_DVBC_ANNEX_A.
>>>
>>> That's said, the difference between a 0.15 and a 0.13 rolloff is not big.
>>> I won't doubt that a demod set to 0.15 rolloff would be capable of
>>> working
>>> (non-optimized) with a 0.13 rolloff.
>>>
>>> What I'm saing is that, if any of the existing drivers currently works
>>> with both Annex A and Annex C, we'll need something equivalent to:
>>>
>>> if (delsys == SYS_DVBC_ANNEX_AC) {
>>> int ret = try_annex_a();
>>> if (ret< 0)
>>> ret = try_annex_c();
>>> }
>>>
>>> For FE_SET_FRONTEND (and the corresponding v5 logic), in order to avoid
>>> regressions.
>>
>>
>>
>> What I was implying:
>>
>> set_frontend/search()
>> {
>> case SYS_DVBC_ANNEX_A:
>> // do whatever you need to do for annex A tuning and return
>> break;
>> case SYS_DVBC_ANNEX_C:
>> // do whatever you need to do for annex C tuning and return
>> break;
>> }
>>
>>
>> ANNEX_AC is a link to ANNEX_A;
>
>
> Yes, I saw your approach.
>
>
>> We never had any ? users to ANNEX_C, so
>> that issue might be simple to ignore.
>
>
> This is hard to say. What I'm saying is that, if any of the current
> drivers works as-is with Annex C, we should assume that someone is using,
> as we don't have any evidence otherwise.
>
> I'm sure there are lots of people running Linux in Japan.
>
> How many of them are using the DVB subsystem is hard to say. The low message
> traffic at the ML for people *.jp is not a good measure, as due to language
> barriers, people may not be posting things there.
>
> A quick grep here on my local copy of the ML traffic (it currently has
> stored
> about 380 days of email, as I moved the older ones to a separate storage
> space)
> still shows 90 messages that has ".jp" inside:
>
> $ grep -l "\.jp" * |wc -l
> 90
>
> 41 of them has the word DVB inside. Ok, there are some false positives there
> too (due to *.jpg), but there are some valid hits also,
>
> Including a commit on this changeset:
> e38030f3ff02684eb9e25e983a03ad318a10a2ea.
> As the cx23885 driver does support DVB-C with stv0367, maybe the committer
> might be using it for DVB-C.
>
> Even if not, I suspect that it is likely to have some DVB-C Annex C users
> out there.
As far as I am aware, most of the services use BCAS2 encryption. There
is no BCAS2 support available as Open Source, other than with sundtek.
Regards,
Manu
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