Oliver Endriss wrote: >Manu Abraham wrote: > > >>On 8/6/07, Michael Krufky <mkrufky@xxxxxxxxxxx> wrote: >> >> >>>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 ??? >>> >>> >>Ideally, what's provided by the demod and not the tuner max/min. The >>tuners max/min should be checked by the demod on setting params. >> >>The upper/lower limits in the demodulator drivers, came from the >>concept of a frontend as a whole. Independant bounds do not make sense >>(except internally -- It is the demod driver that which sets >>parameters for the tuner. The external world doesn't need to know >>what's the limit of the tuner, but only of the frontend as a whole). >> >>Ideally, the demodulator should just demodulate only. There are some >>cases, there are some cases which are not. >> >> > >Ok, I'm trying to put all pieces together: >There might be cases where demod and tuner have different limits. > >So FE_GET_INFO and dvb_frontend_check_parameters() should use the >'smallest common bandwidth': > >freq_min = max(fe->ops.info.frequency_min, fe->ops.tuner_ops.info.frequency_min); > >if (fe->ops.info.frequency_max == 0) > freq_max = fe->ops.tuner_ops.info.frequency_max; >else if (fe->ops.tuner_ops.info.frequency_max == 0) > freq_max = fe->ops.info.frequency_max; >else > freq_max = min(fe->ops.info.frequency_max, fe->ops.tuner_ops.info.frequency_max); > >if (freq_min == 0 || freq_max == 0) > printk(KERN_WARNING "frequency limits undefined - please fix the driver\n"); > >Conclusions: >- A tuner-only driver must set fe->ops.tuner_ops.info. >- Monolithic drivers must set fe->ops.tuner_ops.info or fe->ops.info > (or both). > > I apologize for my delayed response -- I had to leave town unexpectedly. The above is OK with me. As I understand it, we cannot remove fe->ops.info.frequency_max|min because it is part of the userspace API. I wasn't thinking about that fact when I wrote my last email in this thread. We should keep this in mind, for whenever the time comes that we do have to break API compat. Regards, Mike _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
