[linux-dvb] Help please; hacking m920x driver

Aapo Tahkola aet at rasterburn.org
Wed Feb 28 22:59:18 CET 2007


On Thu, 1 Mar 2007 07:11:11 +1100
Nick Andrew <nick-linuxtv at nick-andrew.net> wrote:

> I'm trying to hack the m920x driver for my "LifeView TV Walker Twin"
> DVB-T USB 2.0. Having some success and some failure, cause I'm new
> to this and I mostly don't know what I'm doing.
> 
> The device has an M9206, two TDA10046A, and two TDA8275A. Mine seems
> to be permanently in the "warm" state now, so despite the work I did
> to extract the firmware, it seems I don't need it at the moment.

Both m920x and TDA8275A can work with supplied or eeprom firmware.

> 
> I'm using the latest code from the main hg repository.
> 
> Questions :-
> 
>  - It has 2 tuners and 2 demodulators. I think I found the two
>    demodulators, at addresses 0x10 and 0x16. I have no idea how to
>    represent two of them in the code. You'll notice that I call
>    dvb_attach twice, but it overwrites the return value.
>    Does m920x_state need to be extended for this?

You should probably try with only one set of tuners and demods at first.
I do not think this is currently possible without at least some
hacking. In theory you could define another adapter in
dvb_usb_device_properties.

m9206_i2c_xfer in head does not support i2c messages supplied by
the tda8275 module, thus I would suggest that you work against
msi-digivox-mini-ii.diff .You can simply commit this patch to your
local repo...

> 
>  - I have no idea where the two tuners are. I set up a loop to query
>    all 255 addresses and the module reports failure on the first one
>    then hangs trying to query the second one. The loop technique
>    worked to find the demodulators at least :-)
> 
> I'm running this under vmware emulation so it doesn't break the
> host machine.

Take a look at
http://www.linuxtv.org/pipermail/linux-dvb/2006-November/014682.html
and
http://www.linuxtv.org/pipermail/linux-dvb/2007-February/016252.html .

I haven't yet seen a m920x setup with two demods so I wouldn't know how
the m920x initialization needs to be done. I really didn't even know it
can work with two demods. By examining i2c messages, you should have no
trouble figuring out where those tuners live.

> 
> I've attached my hacked m9206.c module and kernel log.
> 
> Nick.


-- 
Aapo Tahkola



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