Re: [PATCH RFCv10 00/15] DVB QoS statistics API

[Antti Palosaari <crope@iki.fi>]

On 01/17/2013 08:50 PM, Mauro Carvalho Chehab wrote:
> Em Fri, 18 Jan 2013 00:07:17 +0530
> Manu Abraham <abraham.manu@gmail.com> escreveu:
>
>> On Thu, Jan 17, 2013 at 11:57 PM, Antti Palosaari <crope@iki.fi> wrote:
>>
>>>
>>>
>>> Resetting counters when user tunes channel sounds the only correct option.
>>>
>>
>> This might not be correct, especially when we have true Multiple Input Streams.
>> The tune might be single, but the filter setup would be different. In
>> which case it
>> wouldn't correct to do a reset of the counters ona tune. Resetting the counters
>> should be the responsibility of the driver.
>
> I moved the counters reset to the driver's logic on v11. I'm posting the
> patches in a few.
>
>> As I said in an earlier
>> post, anything
>> other than the driver handling any statistical event monitoring, such an API is
>> broken for sure, without even reading single line of code for that API for which
>>   it is written for.
>
> Yes, driver should have full control on it.
>
>>> OK, maybe we will see in near future if that works well or not. I think that
>>> for calculating of PER it is required to start continuous polling to keep up
>>> total block counters. Maybe updating UCB counter continously needs that too,
>>> so it should work.
>>
>>
>> With multi-standard demodulators, some of them PER compute is a by-product
>> of some internal demodulator algorithmic operation. In some cases, it might
>> require a loop in the driver. As I said, again; It is very hard/wrong
>> to do basic
>> generalizations.
>
> Agreed.
>

I think we will have soon kinda consensus everyone could approve! 
Anyhow, I didn't liked that kind of PATCH RFC process. That change was 
too big for PATCH style RFC and it was hard to keep track what going on 
looking those patches. Maybe requirement specification RFCs first and 
when requirements are clear => PATCH RFC for implementation.

What I know understand, requirements are:

signal strength:
==============
Offer both discussed methods.
Simple [0...n] scale and dB...
Driver must support simple scale over dB.

CNR (SNR)
==============
Offer both discussed methods.
Simple [0...n] scale and dB...
Driver must support simple scale over dB.

BER
==============
Offer global BER and per layer BER.
Measure is returned as two numbers, one for error bit count and one for 
total bit count.

uncorrected packets/blocks
==============
Offer global UCB and per layer UCB.
Measure is returned as two numbers, one for uncorrected packet count and 
one for total packet count.

counter reset
==============
counters are reset when channel is tuned



And if we end up returning "simple" values over dB values, then I think 
driver could be simple and implement only dB and dvb-core is responsible 
to convert dB => simple. That should quite be possible as we know which 
dB value is good signal and which is bad signal.


Are these requirements now in line what is spoken?

regards
Antti

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