[mythtv-users] Trouble with DVB-C card, only partially recognized

[Raymond Wagner]

On 02/25/11 15:00, Jurgen Kramer wrote:
> On Fri, 2011-02-25 at 10:41 -0800, Robert McNamara wrote:
>   
>> On Fri, Feb 25, 2011 at 10:24 AM, Jurgen Kramer <gtmkramer at xs4all.nl> wrote:
>>     
>>> On Fri, 2011-02-25 at 10:02 -0800, Robert McNamara wrote:
>>>       
>>>> On Fri, Feb 25, 2011 at 9:59 AM, Jurgen Kramer <gtmkramer at xs4all.nl> wrote:
>>>>         
>>>>> Hi,
>>>>>
>>>>> Today I added an additional Mystique CaBiX-C2 (KNC-ONE clone) PCI DVB-C
>>>>> card to my MythTV setup. The card is only partially recognized by
>>>>> MythTV, in mythtv-setup it shows an
>>>>> additional /dev/dvb/adapterX/frontendX but without the
>>>>> accompanying /dev/videoX. Checking kernel messages reveals it does not
>>>>> register the /dev/video component.
>>>>>           
>>>>
>>>> /dev/video nodes are for analog devices.  Your card is a digital tuner.
>>>>
>>>>         
>>> Thanks for the quick reply. It seems /dev/video devices are still
>>> created for the digital cards. I currently have two working cards:
>>>
>>> [   12.317141] Linux video capture interface: v2.00
>>> [   12.559484] saa7146_vv: saa7146 (0): registered device video0 [v4l2]
>>> [   12.969262] saa7146_vv: saa7146 (1): registered device video1 [v4l2]
>>>
>>> AFAIK digital videocard still use /dev/video to get the (digital)
>>> stream.
>>>       
>> No, that is not correct.  /dev/dvb/frontend# is used for digital
>> devices.  No /dev/video is necessary, /dev/video is for analog devices
>> *only*.
>>
>>     
> OK, I just put one of the working cards in my test machine and presto,
> a /dev/videoX device is created and tvtime and the likes are happy.

TVTime only understands analog framegrabbers.  It cannot use the MythTV
preferred analog MPEG encoder, nor can it use digital tuners.  It is
entirely possible your other card is a hybrid card, that exposes itself
as both a digital _AND_ an analog card.

> My conclusion is that there definitely something amiss with my new card.
> Too bad, will have to RMA it.
>   

As Robert says, digital devices _only_ use nodes in the /dev/dvb folder,
while analog devices provide /dev/video<n> nodes.  I can show you the
/dev contents of one of my backends that has a single fully working
HVR-1250, and no /dev/video<n> nodes.

This is now two MythTV developers claiming those nodes are not needed
for digital tuners, and your card should work fine.  If you wish, we can
have one of the core LinuxTV developers who frequents this list chime in
as well.