[linux-dvb] Nova-S-Plus audio line input

Lawrence Rust lawrence at softsystem.co.uk
Fri Dec 19 12:16:37 CET 2008


On Friday 19 December 2008 11:41:51 Darron Broad wrote:
> In message <200812191127.35952.lawrence at softsystem.co.uk>, Lawrence Rust
> wrote:
>
> Hiya.
>
> >On Thursday 18 December 2008 20:17:41 Darron Broad wrote:
> >> hi
> >>
> >> >I have a Hauppauge Nova-S-plus PCI card and it works great with
> >> > satellite reception.  However, I would also like to use it with an
> >> > external DVB-T box that outputs composite video and line audio but
> >> > when I select the composite video input I can see a picture but get no
> >> > sound.
> >> >
> >> >I'm using kernel version 2.6.24 so I dug around those sources and I see
> >> > in cx88-cards.c that there's no provision for line audio in.  However,
> >> > the latest v4l top of tree sources have added support for I2S audio
> >> > input and 'audioroute's.
> >> >
> >> >So I modded my 2.6.24 sources to support the external ADC and enable
> >> > I2S audio input using the struct cx88_board cx88_boards.extadc flag,
> >> > similar to the changes made in the current top of tree.  This now
> >> > means that I can watch DVB-T :-)  I don't believe the changes affect
> >> > any other cards.
> >> >
> >> >I would like to see support added for the Nova-S-Plus audio line input
> >> > in the kernel tree asap.  What's the best way of achieving this?  I
> >> > can supply a diff for 2.6.24 or the current top of tree.
> >>
> >> I would be interested to see what changes you made to achieve this
> >> and am able to test. Please share your patch for testing.
> >>
> >> Thanks
> >> darron
> >
> >Diffs for linux kernel 2.6.24 andcd out/linux.x86/release/bin/src the 
current v4l tip attached.
> >
> >The change for the current top of tree is minimal - just a few lines in
> > the static configuration data of cx88-cards.c.
> >
> >The changes for 2.6.24 parallel the changes made for audioroutes in the
> >current tip.
> >
> >Note the changes to cx88_alsa.c to remove the tuner volume control if
> > there's no TV tuner and to re-group the switches more logically.  I was
> > thinking of adding some code to adjust the WM8775 gain - what do you
> > think?
> >
> >HTH.
>
> Thanks for that Lawrence. I will test this soon.
>
> With regard to the gain control on the WM8775, perhaps you can
> look at this:
>
> http://hg.kewl.org/v4l-dvb-test/shortlog
>
> You can find some patches here:
> http://hg.kewl.org/v4l-dvb-test/rev/c1d603af3bef
> http://hg.kewl.org/v4l-dvb-test/rev/302d51bf2baf
> http://hg.kewl.org/v4l-dvb-test/rev/8b24b8211fc9
>
> Which sound like they would do what you desire?
>
> I should rebuild these patches soon to for better testing purposes
> but in the meantime please test if you are interested.

Yes, these patches look _exactly_ like what I was thinking of.  The control of 
audio overload was my main priority, together with a nice ALSA interface.  
I'll give them a try and report back.

NB I can build current top of tree, but I'm only testing with my Nova card on 
kernel 2.6.24.  I don't have a proper test m/c setup to try anything too 
bleeding edge.

Thanks.

-- Lawrence Rust



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