Re: STV0299: reading property DTV_FREQUENCY -- what am I expected to get?

[Mauro Carvalho Chehab <mchehab@redhat.com>]

Em 14-08-2012 17:15, Reinhard Nissl escreveu:
> Hi,
> 
> Am 14.08.2012 14:05, schrieb Manu Abraham:
> 
>>> My other device, a STB0899, always reports the set frequency. So it seems
>>> driver dependent whether it reports the actually locked frequency found by
>>> the zig-zag-algorithm or just the set frequency to tune to.
>>
>> The STV0299 blindly sets the value based on a software zigzag (due to simpler
>> hardware), but this might not be accurate enough. On the other hand, the
>> STB0899 internally does zig-zag in hardware for DVB-S2, and partly in
>> software for DVB-S.
>>
>> In any event, the get_frontend callback should return the value that is read
>> from the demodulator registers, rather than the cached original value that
>> which was requested to be tuned.
>>
>> The stb0899 returns only the cached value IIRC. Maybe I will fix this soon,
>> or maybe you can send a patch.
> 
> See the attached patch.
> 
> This is what I get after the patch:
> 
> Sat.    Pol.    Band    Freq (MHz) Set    Freq (MHz) Get    Delta (MHz)
> S19,2E    H    L    10744    10748,474    4,474
> S19,2E    H    L    10773    10777,944    4,944
> S19,2E    H    L    10832    10836,953    4,953
> S19,2E    H    L    10861    10868,774    7,774
> S19,2E    H    L    10920    10924,312    4,312
> S19,2E    H    L    11023    11026,827    3,827
> S19,2E    H    L    11170    11175,423    5,423
> S19,2E    H    L    11243    11248,452    5,452
> S19,2E    H    L    11302    11307,371    5,371
> S19,2E    H    L    11361    11366,427    5,427
> S19,2E    H    L    11420    11425,473    5,473
> S19,2E    H    L    11464    11468,876    4,876
> S19,2E    H    L    11493    11498,421    5,421
> S19,2E    H    L    11523    11529,080    6,080
> S19,2E    H    L    11582    11586,942    4,942
> S19,2E    H    L    11611    11618,785    7,785
> S19,2E    H    L    11641    11645,951    4,951
> S19,2E    H    L    11670    11675,450    5,450
> S19,2E    H    H    11719    11724,970    5,970
> S19,2E    H    H    11758    11763,975    5,975
> S19,2E    H    H    11797    11802,978    5,978
> S19,2E    H    H    11836    11841,972    5,972
> S19,2E    H    H    11875    11880,951    5,951
> 
> I'll have to let VDR "travel" across the transponders several times to see whether I get similar results for the previously mentioned transponder on the stv0299 device.
> 
> Bye.

The patch seems to be working. Anyway, for it to be merged, you'll
need to be sending it together with your SOB (Signed-off-by),
and using the -p1 format e. g. something like:

--- a/drivers/media/dvb/frontends/stb0899_drv.c	2012-08-14 21:59:59.000000000 +0200
+++ b/drivers/media/dvb/frontends/stb0899_drv.c	2012-08-14 21:29:17.000000000 +0200

as otherwise developer's scripts won't get it right.

Thanks,
Mauro.