Re: si2168/dvbsky - blind-scan for DVB-T2 with PLP fails

[Hurda <hurda@chello.at>]

Thanks, this worked.
The kernel of Ubuntu 15.04 already was compiled with dynamic debug, which saved
me a lot of time.
The driver is properly setting stream_id to 1 when needed.

I tried again with the vanilla source and "cmd.args[2] = 0;".
With the vanilla source, it doesn't find any T2-transponders.

With the modified source, the number of found transponders changes every time
I'm scanning.
I did four runs: twice it found one mux, once it found two and once it found
three, but never all four.
I even tried with w_scan-options for longer tuner- and demux-timeouts.

Without changing the position of the antenna or the stick, after reinstalling
the dvbsky-driver, it found all four T2-muxes on the first try.


On 04.06.2015 21:28, Antti Palosaari wrote:
>
>
> On 06/04/2015 08:36 PM, Hurda wrote:
>> How can I enable debug-output to get the log-messages like
>> http://git.linuxtv.org/cgit.cgi/media_tree.git/tree/drivers/media/dvb-frontends/si2168.c#n164 
>>
>> ?
>
> Compile kernel with dynamic debugs. After that you could enable debugs:
> modprobe si2168; echo -n 'module si2168 =pft' > 
> /sys/kernel/debug/dynamic_debug/control
>
> Antti
>
>
>>
>> Am 28.05.2015 07:26, schrieb Antti Palosaari:
>>> On 05/28/2015 01:27 AM, Hurda wrote:
>>>> Hello.
>>>>
>>>> I think I came across a bug in either of the drivers si2168 and dvbsky
>>>> regarding
>>>> blind-scanning DVB-T2-frequencies.
>>>>
>>>> HW: Technotrend CT2-4400v2 (afaik based on or the same as DVBSky T330)
>>>>      demod: Si2168-B40
>>>>      tuner: Si2158-A20
>>>> OS: Ubuntu 15.04 (kernel 3.19)
>>>>
>>>> In Austria, the DVB-T2-service "SimpliTV" is currently airing up to four
>>>> muxes, next to one or two DVB-T-muxes.
>>>> In my region, the frequencies are 490MHz, 546MHz, 690MHz, 714MHz for
>>>> DVB-T2,
>>>> and 498MHz for DVB-T.
>>>> These numbers might be of interest when reading the logs.
>>>>
>>>> The peculiar aspect of these T2-muxes is that they're aired on PLP 1
>>>> without
>>>> there being a PLP 0. I think this is also the root of my problem.
>>>
>>> dvbv5-scan is working, but w_scan not?
>>>
>>> Could you hack si2168.c file and test?
>>>
>>> if (c->delivery_system == SYS_DVBT2) {
>>>     /* select PLP */
>>>     cmd.args[0] = 0x52;
>>>     cmd.args[1] = c->stream_id & 0xff;
>>> //    cmd.args[2] = c->stream_id == NO_STREAM_ID_FILTER ? 0 : 1;
>>>     cmd.args[2] = 0;
>>>     cmd.wlen = 3;
>>>     cmd.rlen = 1;
>>>     ret = si2168_cmd_execute(client, &cmd);
>>>     if (ret)
>>>         goto err;
>>> }
>>>
>>> Antti
>>>
>>>>
>>>>
>>>> When doing a blind-scan using w_scan 20140727 on Ubuntu 15.04 (kernel
>>>> 3.19),
>>>> w_scan does not find any of these four DVB-T2-muxes.
>>>> It just finds the DVB-T-mux.
>>>>
>>>> Logs:
>>>> media-tree_dmesg_lsusb.txt http://pastebin.com/0ixFPMSA
>>>> media-tree_w_scan.txt http://pastebin.com/yyG3jSwj
>>>>
>>>> The found transponder:
>>>> initial_v3_media_build_trunk.conf http://pastebin.com/LmFQavpy
>>>> initial_v5.conf http://pastebin.com/Jx6kymVt
>>>>
>>>> I also tried a fresh checkout from git.linuxtv.org as of last weekend
>>>> and the
>>>> most recent w_scan version (20141122).
>>>>
>>>> As you can see, w_scan tries to tune(?) the DVB-T2-frequencies, but
>>>> ultimately doesn't find anything on them.
>>>>
>>>>
>>>> Then I tried the DVBSky-linux-driver[1]
>>>> (media_build-bst-20150322.tar.gz)[2]
>>>> from their site, which is using a binary called sit2 for this card.
>>>> Using this driver, w_scan found all four DVB-T2-muxes and the DVB-T-mux.
>>>> Additionally, it found the DVB-T2-muxes during the DVB-T-scan.
>>>>
>>>> Logs:
>>>> media_build-bst_dmesg_lsusb.txt http://pastebin.com/vJeDMxtu
>>>> media_build-bst_w_scan.txt http://pastebin.com/yhwAYjen
>>>>
>>>> Found transponders:
>>>> initial_v3_bst.conf http://pastebin.com/ECKQvRWX
>>>> initial_v5_bst.conf http://pastebin.com/CbhY6Hpz
>>>>
>>>> Of course, doing a channel-scan using dvbv5-scan on these transponders
>>>> worked
>>>> too:
>>>>
>>>> dvbv5_sit2.conf http://pastebin.com/3W52bbhv
>>>> dvbv5_sit2.log http://pastebin.com/nc66PTkt
>>>>
>>>> Afterwards, I tried to do a channel-scan with the same initial
>>>> tuning-file
>>>> using the opensource-driver, which also worked:
>>>>
>>>> dvbv5_si2168.conf http://pastebin.com/A6FbqUL1
>>>> dvbv5_si2168.log http://pastebin.com/ewyVPJR2
>>>>
>>>> This should verify that tuning PLP 1 without there being PLP 0 is not
>>>> the issue.
>>>>
>>>>
>>>> Additionally, if you compare the two channel-lists, you find interesting
>>>> differences:
>>>>
>>>> The scan with si2168 has AUTO for "MODULATION" and "INVERSION" for
>>>> DVB-T2-channels, and for "CODE_RATE_LP" and "INVERSION" for
>>>> DVB-T-channels.
>>>>
>>>> The scan with sit2 has the respective values in the channel-list.
>>>>
>>>> The dvbv5-scan-logs also differ, as using sit2 also displays the signal
>>>> quality
>>>> during tuning.
>>>>
>>>>
>>>> I know that there were changes regarding DVB-T2-scanning[3], but as the
>>>> blog-
>>>> article specifically mentions si2168 and w_scan to be fully
>>>> dvbv5-compliant
>>>> and good for using with DVB-T2, I thought you should know about this
>>>> particular problem.
>>>>
>>>>
>>>> In the attachment I've packed the previously linked logs, for archival
>>>> reasons.
>>>>
>>>>
>>>> Thank you for your attention.
>>>>
>>>> [1] http://www.dvbsky.net/Support_linux.html
>>>> [2] http://www.dvbsky.net/download/linux/media_build-bst-150322.tar.gz
>>>> [3] http://blog.palosaari.fi/2014/09/linux-dvb-t2-tuning-problems.html
>>>>
>>>> PS: Interesting comments regarding auto-detection for si2168:
>>>> http://blog.palosaari.fi/2014/09/linux-dvb-t2-tuning-problems.html?showComment=1427233615765#c8591459871945922951 
>>>>
>>>>
>>>>
>>>> http://blog.palosaari.fi/2014/09/linux-dvb-t2-tuning-problems.html?showComment=1427234034259#c6500661729983566638 
>>>>
>>>>
>>>>
>>>
>>
>