Re: [PATCH] dvb_usb_dvbsky: Mygica T230C2 add support for T230C hw version 2

[JP <jp@jpvw.nl>]

On 6/13/19 1:46 AM, JP wrote:
>
>
> On 6/13/19 12:31 AM, Antti Palosaari wrote:
>> On 6/12/19 11:07 PM, Frantisek Rysanek wrote:
>>> On 12 Jun 2019 at 1:28, Antti Palosaari wrote:
>>> [...]
>>>>
>>>> What is that T230C2 stick?
>>> JP has already explained the details, how that name was arrived at.
>>> As previously suggested, I can call it T230C v2 in the descriptive
>>> texts. I'd suggest keeping T230C2 in the USB ID macro (or suggest
>>> a more appropriate name for the macro).
>>>
>>> Here in CZ, a company called Abacus imports and distributes consumer
>>> electronics gadgets under a private brand "EvolveO" - and this is how
>>> the "rebadged OEM Mygica" has reached me.
>>>    http://m.evolveo.com/cz/sigma-t2
>>> This particular T2 dongle is "allover the place" around here, no
>>> other dongle is this broadly available. (Well on our modest market.
>>> We're a nation of 10M people.)
>>>
>>>> Naming sounds like a DVB-C2 capable, but I
>>>> found only T230C model from MyGica site.
>>>>
>>> The local brand's site only mentions DVB-T2.
>>> The 2-page "brief datasheet" of the si2168 that's publically
>>> available only mentions DVB-C, apart from T/T2.
>>>
>>>> And also patch should be split to two logical parts, first add 
>>>> manual ts
>>>> frequency support to si2168 and then other patch which adds device 
>>>> itself.
>>>>
>>> I'll try to find some time and massage that approach into the code.
>>> I have read all the past attempts (example patches) and the
>>> maintainer's polite objections.
>>>
>>>> And which are tuner and demod versions/revisions used for that device?
>>>>
>>> That's reported in dmesg if memory serves... I'll try to find the
>>> answer.
>>>
>>> Frank Rysanek
>>>
>>
>> Yeah, all-in-all:
>> 1) name it T230C v2
>> 2) use manual ts clock speed
>>
>> And according to old usb sniffs from pctv 292e [Si2168B] default 
>> manual ts clock is set to 7.2MHz, which means 57.6Mbit/s datarate, it 
>> should be quite optimal for DVB-T2 max. In theory it could be a 
>> little higher only when 10MHz channel bandwidth and most less error 
>> correction FEC in use. And currently driver is using some config that 
>> uses dynamic ts clock which clocks only when there is data to feed. 
>> For some reason, usb-ts-bridge does not understand that and manual 
>> configuration is needed (ts valid or ts-sync connection?). If 
>> possible use 7.2MHz, if not: set to 10MHz.
>>
> That's perfectly alright with me. I'm now testing that 7.2Mhz value. 
> Hold on.
The driver crashes with the 7.2Mhz value! That was totally not what I 
ever expected.
Recompiled the whole kernel: crashes again. Then tried on debian kernel 
4.19: same thing.
Food for thought?

> And we were thinking in that same line of ts_sync connection.
>
> BTW this is the link for where that value of 10Mhz stems from:
> https://github.com/ljalves/linux_media/issues/164#issuecomment-335011689
>
JP