[linux-dvb] DiB3000MC : autosearch doesn't work

Mario Rossi mariofutire at googlemail.com
Sat Oct 28 14:56:02 CEST 2006


> IIRC Patrick has the datasheet.

Is it held under some kind of non disclosure agreement?

Why don't we create a repository for all datasheets available. I think
the more people check the code, the better it is.

> Also the old driver
> http://castet.matthieu.free.fr/tmp/v4l-dvb-stk3000p-e5798f307b00.tar.gz
> autosearch works  for me.

I need an older kernel to try it. I'll do it tomorrow maybe.

I was trying to compare the 2 versions but it is very hard. The old
driver had a lot of #define s, while in the new one the are plenty of
"magic" numbers which are not easy to understand.

The following could be completely wrong, but this is as far as I got
to understand.

The only big "difference" I can see is about the channel which is used
before auto search starts. It is like an initial guess.

In the new code the initial guess is (regardless of the settings of
the channel required):

fchan.nfft = 1; fchan.guard = 0; fchan.nqam = 2;
fchan.vit_alpha = 1; fchan.vit_code_rate_hp = 2; fchan.vit_code_rate_lp = 2;
fchan.vit_hrch = 0; fchan.vit_select_hp = 1;

which means ( 8K, 1_32, QAM_64, 2_3 .....).

I've changed the code to behave more similar to the old version, where
only the parameters XX_AUTO where given an initial guess (leaving the
others unchanged), which was

( 2K, 1_32, QPSK, 0 for FEC )

That way I can autosearch one parameter at a time and not all together.

In my tests the TRANSMISSION_MODE and the GUARD_INTERVAL cannot be autosearched.

This exaplains why I can auto search BBC ONE (2K, 1_32) and not the
HDTV (8K, 1_32), and when I give the guess the wrong value for the
GUARD INTERVAL it fails.

I still have to investigate something called (in the old driver)
DIB3000MC_REG_SEQ_TPS which seems to have something to do with
TRANSMISSION, GUARD and INVERSION.

Time to eat now.
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