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

Trent Piepho xyzzy at speakeasy.org
Mon Aug 6 22:00:10 CEST 2007

On Mon, 6 Aug 2007, e9hack wrote:
> Michael Krufky schrieb:
> >
> > 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 ???
> >
> I didn't see the ranges from the tuner, because the dvb-c drivers don't use the pll framework. They
> have very simple tuning functions only. We should use both values. One part may be more restrictive
> than the other one.

Most demodulators don't have frequency ranges.  They just take whatever the
tuner gives them at a fixed intermediate frequency.  It's really the tuner
that has the frequency range.

I think it would make more sense for the demodulator drivers to fill
fe->ops.info.frequency_min|max using fe->ops.tuner_ops.info.frequency_min|max.
A frontend driver that doesn't use a separate tuner driver (like DST) would
set the fe->ops.info.frequency_min|max directly.

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