Re: [RESEND] Re: DViCO FusionHDTV DVB-T Dual Digital 4 (rev 1) tuning regression

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Hi,

    The 6MHz patch is for Taiwan only.
    It should not change anything for 7MHz and 8MHz.

Terry

2010/1/7 Robert Lowery <rglowery@xxxxxxxxxxxxxx>:
>> On Wed, 2010-01-06 at 14:20 +1100, Robert Lowery wrote:
>>> > On Mon, 2010-01-04 at 21:27 -0500, Andy Walls wrote:
>>> >> On Mon, 2010-01-04 at 15:27 +1100, Robert Lowery wrote:
>>> >> > > Mauro,
>>> >> > >
>>> >> > > I've split the revert2.diff that I sent you previously to fix the
>>> >> tuning
>>> >> > > regression on my DViCO Dual Digital 4 (rev 1) into three separate
>>> >> patches
>>> >> > > that will hopefully allow you to review more easily.
>>> >> > >
>>> >> > > The first two patches revert their respective changesets and
>>> nothing
>>> >> else,
>>> >> > > fixing the issue for me.
>>> >> > > 12167:966ce12c444d tuner-xc2028: Fix 7 MHz DVB-T
>>> >> > > 11918:e6a8672631a0 tuner-xc2028: Fix offset frequencies for DVB @
>>> >> 6MHz
>>> >> > >
>>> >> > > The third patch does what I believe is the obvious equivalent fix
>>> to
>>> >> > > e6a8672631a0 but without the cleanup that breaks tuning on my
>>> card.
>>> >> > >
>>> >> > > Please review and merge
>>> >> > >
>>> >> > > Signed-off-by: Robert Lowery <rglowery@xxxxxxxxxxxxxx>
>>> >> >
>>> >> > Mauro,
>>> >> >
>>> >> > I'm yet to receive a response from you on this clear regression
>>> >> introduced
>>> >> > in the 2.6.31 kernel.  You attention would be appreciated
>>> >> >
>>> >> > Thanks
>>> >> >
>>> >> > -Rob
>>> >> Robert,
>>> >> The changes in question (mostly authored by me) are based on
>>> >> documentation on what offsets are to be used with the firmware for
>>> various DVB bandwidths and demodulators.  The change was tested by Terry
>>> >> on a Leadtek DVR 3100 H Analog/DVB-T card (CX23418, ZL10353, XC3028)
>>> and
>>> >> some other cards I can't remember, using a DVB-T pattern generator
>>> for
>>> 7
>>> >> and 8 MHz in VHF and UHF, and live DVB-T broadcasts in UHF for 6 MHz.
>>> (Devin,
>>> >>  Maybe you can double check on the offsets in tuner-xc2028.c with any
>>> documentation you have available to you?)
>>> >> I haven't been following this thread really at all as the board in
>>> the
>>> subject line was unfamiliar to me, so sorry for any late response or
>>> dumb
>>> questions by me.
>>> >> May I ask:
>>> >> 1. what are the exact problem frequencies?
>>> >> 2. what is the data source from which you are getting the frequency
>>> information?
>>> >> 3. what does tuner-xc2028 debug logging show as the firmware loaded
>>> when
>>> >> tune to one of the the problem frequencies?
>>> >
>>> >
>>> > Robert,
>>> >
>>> > I just found that ACMA has a very nice compilation licensed DTV
>>> > transmitters in Australia and their frequencies.  Have a look at the
>>> Excel spreadsheet linked on this page:
>>> >
>>> >    http://acma.gov.au/WEB/STANDARD/pc=PC_9150
>>> >
>>> > The DTV tab has a list of the Area, callsign, and DTV center freq. The
>>> Glossary tab mentions that DTV broadcasters can have an offset of +/-
>>> 125
>>> kHz from the DTV center freq.
>>> >
>>> > If you could verify that the frequencies you are using for the problem
>>> stations match the list, that would help eliminate commanded tuning
>>> frequency as source of the problem.
>>>
>>> Andy, I don't think this issue is frequency, it is the removal of the
>>> 500kHz offset.
>>
>> OK.  I forgot there were two offsets at play here: one for the RF
>> frequency and one for the SCODE/Intermediate Frequency.
>>
>> Right, the S-CODE offsets are somewhat of a mystery to me as I don't
>> exactly know the mathematical basis behind them.  The 500 kHz came from
>> the best interpretation Maruo and I could make at the time, but it could
>> very well be the wrong thing.  (I was guessing it came from a relation
>> something like this: 8 MHz - 7 MHz / 2 = 500 kHz)
>>
>> If it is the wrong thing, and it looks like it could be, we can back it
>> out.  As my colleauge, who used to work at CERN, says "Experiment trumps
>> theory ... *every* time".  Terry had positive results, you and Vincent
>> have negative results.  So I'd like to see what Devin finds, if he can
>> test with a DVB-T generator.
>
> Andy,
>
> Resend of my proposed patches attached.
>
> My hypothesis is that 02_revert_e6a8672631a0.diff was really meant to just
> change the ATSC test to DTV6 but at the same time a cleanup that was done
> inadvertently removed the 500kHz offset subtraction for DTV7 introducing
> the defect.  01_revert_966ce12c444d.diff partially fixed this regression
> for Terry, but not for me or Vincent.
>
> I'm having trouble convincing Mauro of this though :), so I would
> appreciate it if Terry could test my patch set and confirm it is ok for
> him.
>
> So in short, my 01 and 02 patches attached revert the changes that break
> tuning for me and 03 re-implements the DTV6 fix, but without the cleanup
> which breaks me.
>
> Please review and comment
>
> -Rob
>
>>
>>
>>
>>> The channel with the biggest problem (most stuttering) is Channel 8 in
>>> Melbourne, which looks correct at 191.625 MHz on the above site.
>>
>> OK.  Vincent must have been the one with all the Sydney stations.
>>
>> DTV Channel GTV8 (Fc = 191.625 MHz at 50 kW) for Melbourne is
>> interesting; it comes from the same towers as the adjacent analog
>> channels HSV7 (Fr = 182.25 MHz @ 200 kW) and GTV9 (Fr = 196.25 MHz @ 200
>> kW).
>>
>> I guess if anything is off center when setting up the XC3028, the analog
>> stations may show up as strong noise - a situation that would not be
>> obvious with a single channel DVB-T signal generator.  GTV8 is probably
>> a good channel for you to use for testing.
>>
>>
>> (BTW, given that the analog channel of where GTV8 now resides would have
>> been Fr = 189.25 MHz, I would have expected GTV8 to really be operating
>> at Fc = Fr + 2.25 MHz = 191.50 MHz and not 191.625 MHz)
>>
>>
>>
>>> With debug enabled on the the current hg tip (stuttering case) we have
>>> divisor= 00 00 2f 58 (freq=191.625)
>>>
>>> With the patch reverted (working case)
>>> divisor= 00 00 2f 38 (freq=191.625)
>>>
>>> Have you reviewed my patch.  It leaves your original DTV6 fix in place,
>>> but reverts the cleanup which broke the offset calculation for me.
>>
>> I don't have a copy in my email archives, I'll have to go check for them
>> on the list archives.
>>
>> Regards,
>> Andy
>>
>>> -Rob
>>>
>>> >
>>> > Regards,
>>> > Andy
>>> >
>>> >
>>> >> BTW, I note that in linux/drivers/media/dvb/dvb-usb/cxusb.c:
>>> >> cxusb_dvico_xc3028_tuner_attach(), this declaration
>>> >>         static struct xc2028_ctrl ctl = {
>>> >>                 .fname       = XC2028_DEFAULT_FIRMWARE,
>>> >>                 .max_len     = 64,
>>> >>                 .demod       = XC3028_FE_ZARLINK456,
>>> >>         };
>>> >> really should have ".type = XC2028_AUTO" or ".type = XC2028_D2633",
>>> but
>>> since XC2028_AUTO has a value of 0, it probably doesn't matter.
>>> Regards,
>>> >> Andy
>>
>>
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