[mythtv-users] Multi-standard DVB frontend support?

Tue May 1 17:57:09 UTC 2012

On 1 May 2012 18:55, Mike Perkins <mikep at randomtraveller.org.uk> wrote:

> On 01/05/12 14:41, Niklas Brunlid wrote:
>
>> On 1 May 2012 12:18, Mike Perkins<mikep at randomtraveller.**org.uk<mikep at randomtraveller.org.uk>>
>>  wrote:
>>
>>  On 30/04/12 22:10, Niklas Brunlid wrote:
>>>
>>>  One week with no replies, figured I'd bump this at least once. :)
>>>> On 23 April 2012 10:01, Niklas Brunlid<prefect47 at gmail.com>   wrote:
>>>>
>>>>
>>>>> Apologies for cross-posting to the dev list, but it seemed appropriate.
>>>>>
>>>>> I'm wondering if there are any plans for support of multi-standard
>>>>> frontends? I came across
>>>>> http://article.gmane.org/****gmane.linux.drivers.video-**<http://article.gmane.org/**gmane.linux.drivers.video-**>
>>>>> input-infrastructure/45723/****match=290ewhen<http://article.**
>>>>> gmane.org/gmane.linux.drivers.**video-input-infrastructure/**
>>>>> 45723/match=290ewhen<http://article.gmane.org/gmane.linux.drivers.video-input-infrastructure/45723/match=290ewhen>
>>>>> >
>>>>>
>>>>> looking for clues as to why my PCTV 290e stopped working when I
>>>>> upgraded
>>>>> my
>>>>> Fedora 15 (now 16) combined backend/frontend server to a 3.x kernel and
>>>>> it
>>>>> mentions that it was introduced in Linux DVB API v5.4 or something.
>>>>>
>>>>>
>>>>>   I think you'll have to explain in a little more detail exactly what
>>>> your
>>>>
>>> problem is, if you want someone to look at it. I run a back end with
>>> 2xDVB-T cards and a PCTV-290e USB dongle for HD and I have no problems at
>>> all. I'm running a Debian 3.0.x kernel on that box.
>>>
>>> Where exactly does your front end enter into this? Tuners are in back
>>> end(s). If you mean you have a problem displaying SD/HD content, that's
>>> got
>>> nothing to do with your tuners.
>>>
>>>
>> My mail was basically a shot in the dark since my 290e doesn't work since
>> the upgrade. Sorry for the confusion - I don't mean frontend as in the
>> MythTV frontend, but as the device in /dev/dvb/adapterN/*frontend*N.
>>
>>
>> As I understand it, in the new Linux DVB API, the
>> /dev/dvb/adapterN/frontend is no longer split into frontend0 and frontend1
>> if your device is multi-standard. The 290e supports DVB-T2 and DVB-C on
>> the
>> same input but has to be told which one to use, and earlier this was
>> solved
>> by having device 0 represent DVB-T2 and device 1 represent DVB-C. Although
>> you had to trick it by symlinking all the other devices - demux0, dvr0 and
>> net0 - to demux1, dvr1 and net1, since only frontend1 was created.
>>
>> In the new API the application has to know about the change, and
>> explicitly
>> tell the device to switch between the standards. From my limited
>> understanding it might be something like
>> http://www.linuxtv.org/wiki/**index.php/S2API<http://www.linuxtv.org/wiki/index.php/S2API>that has to be used?
>>
>> Since this change, my box can no longer use the 290e DVB-C for input.
>> Maybe
>> it works on your system because you use DVB-T2?
>>
>> BTW, I also found some discussions specifically about the 290e here:
>> http://www.mail-archive.com/**linux-media@vger.kernel.org/**msg31845.html<http://www.mail-archive.com/linux-media@vger.kernel.org/msg31845.html>
>>
>> I did get dvbscan or w_scan or something to work against
>> /usr/share/dvb/DVB-C/se-comhem last week, although it seems to use DVB-C2.
>> w_scan claims support for Linux DVB API 5.3 and says that the device is
>> buggy:
>>
>>
>> $ w_scan -A2 -fc -cSE -G -X |tee .czap/channels.conf
>> w_scan version 20120112 (compiled for DVB API 5.3)
>> using settings for SWEDEN
>> DVB cable
>> DVB-C
>> scan type CABLE, channellist 7
>> output format czap/tzap/szap/xine
>> WARNING: could not guess your codepage. Falling back to 'UTF-8'
>> output charset 'UTF-8', use -C<charset>  to override
>> Info: using DVB adapter auto detection.
>>         /dev/dvb/adapter0/frontend0 ->  CABLE "Sony CXD2820R": very good
>> :-))
>>
>> Using CABLE frontend (adapter /dev/dvb/adapter0/frontend0)
>> -_-_-_-_ Getting frontend capabilities-_-_-_-_
>> Using DVB API 5.5
>> frontend 'Sony CXD2820R' supports
>> DVB-C2
>> INVERSION_AUTO
>> QAM_AUTO
>> FEC_AUTO
>> FREQ (45.00MHz ... 864.00MHz)
>> This dvb driver is *buggy*: the symbol rate limits are undefined - please
>> report to linuxtv.org
>> -_-_-_-_-_-_-_-_-_-_-_-_-_-_-_**-_-_-_-_-_-_-_-_
>> 73000: sr6900 (time: 00:00) sr6875 (time: 00:05)
>>
>>  Hmm. A strange one.
>
> micheal at ruby:~$ uname -a
> Linux ruby 3.2.0-0.bpo.1-amd64 #1 SMP Sat Feb 11 08:41:32 UTC 2012 x86_64
> GNU/Linux
> micheal at ruby:~$
>

Nothing strange about my system:

*# modinfo cxd2820r*
filename:
/lib/modules/3.3.2-6.fc16.x86_64/kernel/drivers/media/dvb/frontends/cxd2820r.ko
license:        GPL
description:    Sony CXD2820R demodulator driver
author:         Antti Palosaari <crope at iki.fi>
depends:        i2c-core,dvb-core
intree:         Y
vermagic:       3.3.2-6.fc16.x86_64 SMP mod_unload
parm:           debug:Turn on/off frontend debugging (default:off). (int)

*# uname -a*
Linux u033 3.3.2-6.fc16.x86_64 #1 SMP Sat Apr 21 12:43:20 UTC 2012 x86_64
x86_64 x86_64 GNU/Linux

*# ls -l /dev/dvb/adapter_290e/*
total 0
lrwxrwxrwx 1 root root 18 May  1 15:32 demux0 -> ../adapter0/demux0
lrwxrwxrwx 1 root root 16 May  1 15:32 dvr0 -> ../adapter0/dvr0
lrwxrwxrwx 1 root root 21 May  1 15:32 frontend0 -> ../adapter0/frontend0
lrwxrwxrwx 1 root root 16 May  1 15:32 net0 -> ../adapter0/net0

*# ls -l /dev/dvb/adapter0*
total 0
crw-rw----+ 1 root video 212, 5 May  1 15:32 demux0
crw-rw----+ 1 root video 212, 6 May  1 15:32 dvr0
crw-rw----+ 1 root video 212, 4 May  1 15:32 frontend0
crw-rw----+ 1 root video 212, 7 May  1 15:32 net0

> I'm using DVB-T2, yes. The most recent time I rescanned I noticed that
> there was a DVB-C option which came up as .../frontend1. This means that
> I'm not seeing what you are, unfortunately, both my options are still being
> presented separately.
>

Do you still have the frontend1 entry?

> I'm not sure how this new arrangement you've described works with respect
> to mythtv. I'd sure like to know, because it's going to bite everyone else
> who uses the 290e eventually.
>

If it's a matter of adding support for S2API then it seems to me that there
is code out there in several applications already (Kaffeine, VDR, VLC). I
think I saw some patch code for some of them, though I didn't understand it
:) . But the DVB API docs are not updated from v3 yet.

/ Niklas
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