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

[Antti Palosaari <crope@iki.fi>]

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
>>>
>>>
>>
>

-- 
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