[linux-dvb] Re: [video4linux-cvs] Add support for the Avermedia 777 DVB-T card

Hartmut Hackmann hartmut.hackmann at t-online.de
Mon Jan 30 21:13:08 CET 2006


Hi

Michael Krufky wrote:
> video4linux-cvs-sender at linuxtv.org wrote:
> 
>> From: Jose Alberto Reguero  <jareguero at telefonica.net>
>> Add support for the Avermedia 777 DVB-T card
>>
>> Signed-off-by: Jose Alberto Reguero <jareguero at telefonica.net>
>> Signed-off-by: Hartmut Hackmann <hartmut.hackmann at t-online.de>
> 
> 
> This patch causes the following warnings during the build:
> 
> saa7134-tvaudio.c: In function 'tvaudio_setmode':
> saa7134-tvaudio.c:309: warning: enumeration value 'TVAUDIO_AM_MONO' not 
> handled in switch
> saa7134-tvaudio.c: In function 'tvaudio_getstereo':
> saa7134-tvaudio.c:439: warning: enumeration value 'TVAUDIO_AM_MONO' not 
> handled in switch
> saa7134-tvaudio.c: In function 'tvaudio_setstereo':
> saa7134-tvaudio.c:505: warning: enumeration value 'TVAUDIO_AM_MONO' not 
> handled in switch
> 
Sorry, my fault. This is due to an older change i forgot to commit.
I will do this this evening.

> Also, please skip below to the function: static int 
> mt352_aver777_pll_set , for more comments.
> 
<snip>
> 
> Why is all this tuner programming (below) hardcoded into the card 
> driver?  I've noticed a LOT of this in saa7134-dvb.c  Most of these can 
> be converted to use dvb-pll, and I see no reason why new code should be 
> accepted this way.  We are trying to have consistant looking code, and 
> this is counter-productive.  Please re-do this function to use dvb-pll, 
> so that other devices that have the same tuner can share its programming.
> 
This has historical / practical reasons.
1) When i started extending the saa1734-dvb.c, there simply was no
    dvb-pll module. I simply did it the same was as it was i.e. in budget-ci.
2) Philips recommends to initialize the RF AGC differently for analog TV
    and DVB. Appropriate functions are not jet in dvb-pll. This is the case
    i.e. for TU1216, TU1316, FMd1216ME.
3) A whole bunch of the tuning code is for TDA8275(A). They require a
    programming *sequence* which isn't supported by dvb-pll either.
    Additionally, this chip has a very special IF interface and can only
    work with few channel decoders. It is not very likely that it will ever
    occur i.e. with a connexant PCI bridge.

I also wish to remove as much much as possible of the PLL code from
saa7134-dvb. But since i need to extend the dvb-pll interface, i have to
go throught the big procedure with RFC and so on. I hope i can do this
this spring, together with a rework of the tda1004x api.

The MT352 channel decoder has its own I2C master with the tuner attached
to it. This is why it needs a different tuning function. I submitted this
patch since i wish to do the movement to dvb-pll in one step.

Accepting this for the time being does no harm. And sorry, my time is
limited, i can not do everything immedeately.

Hartmut



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