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Re: tuner, code for discuss




On Mon, 14 Sep 2009 08:55:22 -0400
Michael Krufky <mkrufky@xxxxxxxxxxxxxx> wrote:

> On Thu, Sep 10, 2009 at 1:25 AM, Dmitri Belimov <d.belimov@xxxxxxxxx>
> wrote:
> > Hi All
> >
> > This is my next patch.
> >
> > Changes:
> > 1. By default charge pump is ON
> > 2. For radio mode charge pump set to OFF
> > 3. Set correct AGC value in radio mode
> > 4. Add control gain of AGC.
> > 5. New function simple_get_tv_gain and simple_set_tv_gain for
> > read/write gain of AGC. 6. Add some code for control gain from
> > saa7134 part. By default this control is OFF 7. When TV card can
> > manipulate this control, enable it.
> >
> > Main changes is control value of AGC TOP in .initdata =
> > tua603x_agc112 array. Use this value for set AGC TOP after set freq
> > of TV.
> >
> > I don't understand how to correct call new function for read/write
> > value of AGC TOP.
> >
> > What you think about it??
> >
> 
> [patch snipped]
> 
> >
> >
> > With my best regards, Dmitry.
> 
> Dmitry,
> 
> The direct usage of .initdata and .sleepdata is probably unnecessary
> here --  If you trace how the tuner-simple driver works, you'll find
> that simply having these fields defined will cause these bytes to be
> written at the appropriate moment.
> 
> However, for the actual sake of setting this gain value, I'm not sure
> that initdata / sleep data is the right place for it either.  (I know
> that I recommended something like this at first, but at the time I
> didn't realize that there is a range of six acceptable values for this
> field)
> 
> What I would still like to understand is:  Who will be changing this
> value?  I see that you've added a control to the saa7134 driver -- is
> this to be manipulated from userspace? 

Yes

> Under what conditions will somebody want to change this value?  

for SECAM with strong signal we have wide white crap on the screen.
Need reduce value of AGC TOP.

For weak signal need increase value of AGC TOP
Ajust value of AGC TOP can get more better image quality.

> How will users know that they need to alter this gain value?

By default use value from .initdata
v4l2-ctl can modify this value or via some plugins for TV wach programm.

End-user programm for watch TV IMHO now is very poor.

With my best regards, Dmitry.

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