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

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> Hi Rob
>
> I missed your followup and tested the 'revert.diff' patch, attached
> for reference.
> I have been slow replying because I've been scratching my head over the
> results.
>
> I used 'signaltest.pl' to test[1], which uses tzap under the hood.
> Perhaps this is not the best choice, but I wanted something that I thought
> would
> allow objective comparisons. That's trickier than I thought...
> Unfortunately I only discovered last night how easy 'vlc
> ./channels.conf' makes doing quick visual checks. I didn't have enough
> time to re-patch and test again.
>
> My test procedure was:
>  - get a baseline with tzap and signaltest.pl
>  - patch, make, install. cold boot.
>  - test with tzap and signaltest.pl
>  - revert patch, for the moment.
>
> I tested two kernels, and both cards. I tested all the tuners but I'll
> spare you that for now.
>
>  * 2.6.24-23-rt + v4l (c57f47cfb0e8+ tip)
>
>    I got rather different baseline results. All channels had
> significantly higher BER
>    than I'd noticed before. After patching, snr on some channels
> seemed a little higher
>    and BER was lower. On ch9, I think snr was up and BER improved a
> little.
>
>   here are the signaltest summary tables:
>   without patch. usb device (dvb0) usbid db78:0fe9
>  Frequency       Signal          Ber             Unc
>  =========       ========        ========        ========
>  177500000         76.0 %           322.6           672.4  Seven
>  191625000         76.0 %           320.2          1783.3  Nine
>  219500000         76.8 %           329.8          2948.2  Ten
>  226500000         76.9 %           296.6          4885.0  ABC
>  571500000         77.0 %           542.0          7529.4  SBS
>  578500000         77.1 %           539.5         10669.7  D44
>
>  with patch. usb device (dvb0) usbid db78:0fe9
>  Frequency       Signal          Ber             Unc
>  =========       ========        ========        ========
>  177500000         76.6 %             2.3             0.0
>  191625000         77.0 %           235.5            83.3
>  219500000         76.9 %           288.0           501.8
>  226500000         76.9 %           295.1          1416.4
>  571500000         77.0 %           523.4          3980.0
>  578500000         77.1 %           549.9          7409.4
>
>  without patch. pcie device (dvb1) pciid db78:18ac
>  Frequency       Signal          Ber             Unc
>  =========       ========        ========        ========
>  177500000         71.2 %             3.1             0.0
>  191625000         21.7 %           645.4           246.4
>  219500000         73.6 %             1.9          1632.0
>  226500000         73.5 %             2.8          1632.0
>  571500000         73.9 %            13.6          2134.6
>  578500000         72.7 %            58.2          6393.4
>
>  with patch. pcie device (dvb1) pciid db78:18ac
>  Frequency       Signal          Ber             Unc
>  =========       ========        ========        ========
>  177500000         73.2 %             4.0             0.0
>  191625000         74.0 %            37.0             0.0
>  219500000         73.9 %             0.0             0.0
>  226500000         73.0 %             4.6             0.0
>  571500000         74.2 %            76.7           193.6
>  578500000         72.8 %           213.8          4480.3
>
>
>  * 2.6.31-14-generic + v4l (19c0469c02c3+ tip)
>   Hard to say if I'm seeing an improvement.
>
> before patching - adapter0 usbid db78:0fe9
> Frequency       Signal          Ber             Unc
> =========       ========        ========        ========
> 177500000         75.5 %           293.7          1926.4
> 191625000         75.9 %           363.2          2993.3
> 219500000         76.7 %           304.5          4225.8
> 226500000         76.9 %           223.8          6153.3
> 571500000         77.0 %           491.7          8726.0
> 578500000         77.1 %           558.9         11787.1
>
> adapter0 repeat usbid db78:0fe9 (not sure what happened to UNC here..)
> Frequency       Signal          Ber             Unc
> =========       ========        ========        ========
> 177500000         75.9 %           327.9         13893.6
> 191625000         76.0 %           392.8         14939.0
> 219500000         76.7 %           252.0         16052.0
> 226500000         76.8 %           254.0         18063.1
> 571500000         76.9 %           533.2         20644.1
> 578500000         76.9 %           464.1         23836.8
>
> after patching - adapter0 usbid db78:0fe9
> Frequency       Signal          Ber             Unc
> =========       ========        ========        ========
> 177500000         76.3 %             2.5             0.0
> 191625000         76.8 %           227.6           119.0
> 219500000         76.8 %           262.6           604.5
> 226500000         76.8 %           282.7          1545.4
> 571500000         77.0 %           486.8          3541.7
> 578500000         77.1 %           521.5          6537.7
>
>
> before patching - adapter1 pciid db78:18ac
> Frequency       Signal          Ber             Unc
> =========       ========        ========        ========
> 177500000         70.9 %             0.0             0.0
> 191625000         69.8 %             2.7             0.0
> 219500000         73.2 %             4.1             0.0
> 226500000         73.4 %             4.5             0.0
> 571500000         74.0 %             0.0             0.0
> 578500000         72.3 %           125.7          3589.3
>
> after patching - adapter2 pciid  db78:18ac  (enumeration order changed)
> Frequency       Signal          Ber             Unc
> =========       ========        ========        ========
> 177500000         73.6 %             0.6             0.0
> 191625000         74.2 %             0.0             0.0
> 219500000         74.0 %             4.9             0.0
> 226500000         73.3 %           163.2           349.7
> 571500000         74.4 %           267.0          1014.6
> 578500000         72.7 %            70.7          4906.0
>
> Thoughts? What's your test procedure?

Hi Vince

My test procedure is to use mythtv :)

The 2.6.28 ubuntu 9.04 (Jaunty) kernel worked perfectly, but the 2.6.31
ubuntu 9.10 (karmic) kernel and v4l-dvb tip stutters particularly on
channel 9.  I then started browsing which changes were made between the
two kernels and found reverting the patches resolved the problem.  I have
now been using the reverted drivers for over a week and the stuttering is
completely gone.

Sorry I'm not familiar with all the statistics you are quoting above to
know good from bad.  I just know my results :)  Hopefully someone more
knowledgeable can comment

-Rob
>
> Cheers
> Vince
>
>
>
> [1] http://linuxtv.org/wiki/index.php/Testing_reception_quality
>


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