[linux-dvb] [patch] Add support for different tuning algorithms

Andrew de Quincey adq_dvb at lidskialf.net
Tue Nov 15 20:01:20 CET 2005


On Tuesday 15 Nov 2005 18:40, Manu Abraham wrote:
> Andrew de Quincey wrote:
> >On Tuesday 15 Nov 2005 18:07, Felix Domke wrote:
> >>Andrew de Quincey wrote:
> >>>Hi, this patch allows frontends (and the user) to select from one of
> >>>several different tuning algorithms. The patch adds four possibilities:
> >>>1) SW - the current dvb-kernel software zigzag code.
> >>>2) HW - the hardware supports zigzagging internally (e.g. DST), so use
> >>>that as it will be faster.
> >>>3) ADAPTIVE - frontend-specific code exploiting frontend-specific
> >>>features. 4) SIMPLE - just set the frontend once and do nothing else
> >>>(e.g. for frequency scanner apps).
> >>
> >>Though I didn't test this, i strongly agree that we need this. I don't
> >>think it should be user selectable, though (except for the "SIMPLE"
> >>mode) - either the frontends supports a specific algorithm or not.
> >>Otherwise i fear that user applications start to workaround frontend
> >>driver bugs by selecting another algorithm...
> >
> >Hmm, yeah thats a good point. The userspace API should _really_ just be
> >switchable between "standard" and "scan" mode.
> >
> >What constitutes "normal" mode is then up to the innards of the driver.
> > OK, will update the patch to reflect this.
>
> But that will apply to the adaptive algo only probably, since there
> cannot be an alternative for the HW_ALGO as it will be implemented in
> Hardware and no point in doing it otherwise. So the only 2 cases left
> would be S/W and and ADAPTIVE, so switching between "standard" and scan"
> mode might not make any difference.. ?
>
> Or do you mean that the user does not have any option to switch between
> ADAPTIVE and SW .. ?

Yup, the second one. I want the user to be able to switch between "normal" and 
"scan" mode. It perhaps isn't useful for the DST, but it would be for most 
other frontends.



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