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

[Antti Palosaari <crope@iki.fi>]

On 01/15/2013 04:49 PM, Antti Palosaari wrote:
> I am a little bit lazy to read all those patches, but I assume it is
> possible:
> * return SNR (CNR) as both dB and linear?
> * return signal strength as both dBm and linear?
>
> And what happens when when multiple statistics are queried, but fronted
> cannot perform all those?
>
> Lets say SS, SNR, BER, UCB are queried, but only SS and SNR are ready to
> be returned, whilst rest are not possible? As I remember DVBv5 API is
> broken by design and cannot return error code per request.

OK, I read that patch still. All these are OK as there is SCALE flag 
used to inform if there is measurement or not available.
No anymore question about these.

Issues what I still would like to raise now are:

1) How about change unit from dB/10 to dB/100 or even dB/1000, just for 
the sure?

2) Counter are reset when DELIVERY SYSTEM is set, practically when 
tuning attempt is done. There is new callback for that, but no API 
command. Functionality is correct for my eyes, is that extra callback 
needed?

3) Post-BER. I don't need it, but is there someone else who thinks there 
should be both pre-BER and post-BER? IMHO, just better to leave it out 
to keep it simple. In practice both pre-BER and post-BER are running 
relatively, lets say if pre-BER shows number 1000 then post-BER shows 
only 10. Or pre-BER 600, post-BER 6. Due to that, I don't see much 
interest to return it for userspace. Of course someone would like to 
know how much inner coder is working and fixing error bits and in that 
case both BERs are nice...

4) Returning bit counts as BER and UCB means also driver should start 
polling work in order to keep driver internal counters up to date. 
Returning BER as rate is cheaper in that mean, as driver could make 
decision how often to poll and in which condition (and return values 
from cache). Keeping track of total bit counts means continuous polling!


regards
Antti

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