[linux-dvb] Nova-S-Plus audio line input
lawrence at softsystem.co.uk
Sat Jan 3 12:20:35 CET 2009
On Friday 19 December 2008 11:41:51 Darron Broad wrote:
> In message <200812191127.35952.lawrence at softsystem.co.uk>, Lawrence Rust
> >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 and 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?
> Thanks for that Lawrence. I will test this soon.
> With regard to the gain control on the WM8775, perhaps you can
> look at this:
> You can find some patches here:
> 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.
I've been running those patches for the last week now with no problems. I did
find that L-R balance wasn't working properly but it's a simple fix.
I also patched cx88-alsa.c so that I could use an ALSA GUI (kmix) to set the
input level. There's very little difference in this file between 2.6.24 and
top of tree so the patch should be OK for most versions.
Patches for 2.6.24 attached. The patch to wm8775.c is pretty similar to your
original but with these small changes:
- The wm98875 is initialised in I2S mode, not left justified, for proper
operation with the cx88.
- The ALC setup code is left in but conditionally compiled out rather than
removed - in case someone should prefer ALC.
- wm8775_set_audio doesn't set the LRBOTH bit in R21. This fixes the problem
-- Lawrence Rust
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