[mythtv-users] PCM Volume Control on nForce2 (Chaintech 7NIF2)?

[Dave Steinberg]

Hi all,

There's been much enthusiasm on the list lately for nForce2-based
motherboards, and especially the Chaintech 7NIF2.  I had been struggling
with the usual ivtv DMA issues on a VIA-based motherboard, and so I
decided to treat myself to a replacement.  I installed my new 7NIF2 last
night.

The experience has been mostly positive (more on that below), but I'm
having one "problem" that I'd really like to find a certain answer for.
I'm using the ALSA intel8x0 driver (version 1.0.3).  PCM and CD audio (the
only two sources I've tried so far) work, but here's the issue: there
seems to be no way to control the volume for PCM.  In alsamixer, the PCM
slider is empty, with no number, and doesn't respond to the up or down
arrows.  It can only be muted and unmuted.  Morever, PCM audio isn't even
affected by the Master volume.  In myth, [ and ] do nothing: the volume,
unless muted, is always 100%.  I've googled, and I'm seeing claims that
the hardware has no support for mixing PCM at all, and that it would have
to be mixed in software.

Is this true?  Has anyone used the proprietary OSS-based driver, and does
it allow you to control the PCM volume?  Alternately, has anyone been able
to control it using the ALSA driver?

The quality of the sound isn't impressive, either -- it's noticeably worse
than the via82xx on my previous motherboard.  If the device can't mix PCM,
I probably won't even bother with it anymore, and I'll just try to get my
hands on a "real" sound card.

With my question out of the way, I'll share my other observations and
impressions on the motherboard.  Overall, I think it's a really nice
board.  The integrated video works great with the 4363 driver.  I haven't
had any problems with ivtv yet, although I'll post an update if that
changes.  Myth seems much snappier, and it doesn't stutter when I quickly
cycle through the channels in the program guide anymore.

I was very pleasantly surprised to find that there's an open-source driver
for the integrated network device in the 2.4.26 kernel.  Apparently, it
was written from a reverse-engineered specification.  The mind boggles at
NVIDIA's backwards approach to Linux support.  Just think how much effort
they could have saved if they'd just released the specs in the first
place!  Same thing for sound driver: why take on the responsibility of
maintaining their own fork instead of contributing directly to the
exiting intel8x0 drivers?  Are there supposed to be some major competitive
advantages hidden away in this commodity hardware?

More good news: Chaintech has replaced that north bridge fan with a big
honkin' heatsink.

The board's layout is a bit funky, with the IDE connectors on the far end
of the board.  I had to replace my nice, round 1-foot cables with my old,
flat 18 inchers in order to plug the drives in.  Right next to that, at
the front of the board, is the power connector for the case fan, which is
of course mounted on the back of the case.  As has been reported here
before, the SPDIF connector has been removed from the board.  There are
traces, but no pins.

That's about it so far.  If anyone has an answer, definitive or not, to
my PCM question, I'd really appreciate hearing it.

BTW, this is my first time posting on the list, so I'd like to say thanks
and congratulations to Isaac and everyone else who has contributed to
MythTV.

Thanks all!

Cheers,
Dave