[linux-dvb] [PATCH] Fix the min/max frequencies of some DVB-C frontends

Michael Krufky mkrufky at linuxtv.org
Mon Aug 6 21:16:31 CEST 2007


Oliver Endriss wrote:
> Michael Krufky wrote:
>   
>> e9hack wrote:
>>     
>>> Hi,
>>>
>>> the min frequencies of the DVB-C frontends are wrong. In Europe, the center frequency of the lowest
>>> channel is 50.5MHz and not 51MHz. All known cards with the stv0297/tda0002x/ves1820 frontend are
>>> able to tune to this frequency. I've changed the range to the lowest channel - 1/2 bandwidth and the
>>> highest channel + 1/2 bandwidth. For the design of the dvb driver, the frequency ranges must be part
>>> of the tuner and not of the frontend itself. The same frontend may be used for different tuners. The
>>> attached patch does only fix the ranges and not the design.
>>>       
>> Now I'm beginning to have doubts about Oliver's original patch:
>>
>> dvb_frontend: Range check of frequency and symbol rate
>> http://linuxtv.org/hg/v4l-dvb/rev/8186a34dd0a6
>>
>> Should we be checking fe->ops.tuner_ops.info.frequency_min|max , instead of
>> fe->ops.info.frequency_min|max ???
>>     
>
> Hm, I was not aware that there is another info.frequency_min|max
> in tuner_ops. :-(
>
> Do we need both of them?
I think it's most appropriate to keep tuner_ops.info.frequency_min|max ,
since it is the tuner that we're talking about.  If the demodulator
itself does not have such limitations, then we should not have such a
field in the demod ops.info section.

I believe that this is leftover from before Andrew's original dvb tuner
refactoring.

Cheers,

Mike




More information about the linux-dvb mailing list