pvr250 can't tune above channel 11

John-Mark Gurney gurney_j at resnet.uoregon.edu
Sun Jan 16 12:21:16 PST 2005

David C. Myers wrote this message on Sun, Jan 16, 2005 at 09:08 -0800:
> John-Mark Gurney wrote:
> >Yep, by default the PVR-250 always assumes that the channels are
> >cable channels...
> >
> >What I did is modify the appropriate tuner in the:
> >const struct cxm_tuner
> >cxm_tuners[CXM_TUNER_TYPES] = {
> >
> >to remove the &us_cable_channels and replace it with NULL...  It always
> >chooses the cable channels over the air ones...
> >
> >Hope this helps.
> Nope.  Identical behavior.

you could insert around lines 427-429 which say:
        sc->tuner_channels = sc->tuner->channels.cable
                             ? sc->tuner->channels.cable
                             : sc->tuner->channels.air;

	if (sc->tuner->channels.cable == NULL)
		printf("using air channels\n");

This will help you make sure that you got the correct tuner..

> This doesn't make sense to me anyway, since the us_air_channels 
> structure defines a max_channel of 69.  us_cable_channels is even 
> higher, 125.  Regardless of which it chooses, it ought to go to at least 
> 69, right?  What's the significance of channel 11?

Not exactly...  the us_cable and us_air define different sets of
frequencies...  and cxm won't tune to a channel if there is no
signal...  (or at least it will through an error if it can't find
a signal)..  So, you have to make sure there is a signal there before
trying to tune it..  (yeh, it's one of my complaints)..

it's not actually 11, it's channel 13...  above channel 13, they are
UHF, and 13 and below are VHF...  Different parts of the spectrum...
If you look at the definitions, they have different set of frequencies..
the table works by base channel and frequency, and then step for each
channel above.. it you notice, channel 14 starts at different frequencies
for cable and air..   so, the over the air channels >=14 won't start till
about cable channel 65.. but even then, you'll be about 2mhz off, and
it probably won't tune..

We really need to pull the frequency tuning stuff into a seperate module
of the kernel...  So every tuning program doesn't have to reimplement it..

  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."

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