[linux-dvb] AVerMedia AverTV DVB-T USB 2.0 (A800) question

Patrick Boettcher patrick.boettcher at desy.de
Sun Mar 5 11:37:58 CET 2006


it seems to be Gunther is sending his requests mails "blindly" to everyone 
and creates confusion. Sorry to say, but this is the second time I saw a 
user getting slightly confused by Gunther requesting infos for his gallery 
as an answer to a driver-problem-mail.

Although I like the idea of the galery, there must be a better way to 
acquire information.

On Sun, 5 Mar 2006, Doug Scoular wrote:

>   must be listening for other driver related tuning events.
> static int dib3000mc_read_signal_strength(struct dvb_frontend* fe, u16 
> *strength)
> {
>       struct dib3000_state* state = fe->demodulator_priv;
>       u16 val = rd(DIB3000MC_REG_SIGNAL_NOISE_LSB);
>       *strength = (((val >> 6) & 0xff) << 8) + (val & 0x3f);
>       *strength = 0xffff; // Doug's disgusting frig!
>       deb_stat("signal: mantisse = %d, exponent = %d\n",(*strength >> 8) & 
> 0xff, *strength & 0xff);
>       return 0;
> }

Even with this "fix" mythtv has problems?

I have to admit, the way the signal strength is currently calculated is 
wrong and stupid.

Problem is, to have really correct RF power calculation we need more 
information on the board and floating point operations in the kernel.

OTOH, I repeat myself here, I don't see the reason, why MythTV is taking 
the Signal strength into account and drops a receiver from the list, when 
it is zero. In DVB we have much easier values to see if the stream is 
maybe garbled or not and this is the UNC and BER.

Maybe it is worth for mythtv to add an option to disable the consideration 
of signal strength and SNR when using it with DVB.


   Mail: patrick.boettcher at desy.de
   WWW:  http://www.wi-bw.tfh-wildau.de/~pboettch/

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