[alsa-devel] [Intel-gfx] Problems with HDMI audio on Intel DG45FC motherboard

[Wu Fengguang]

On Thu, Nov 05, 2009 at 05:06:22PM +0800, David Härdeman wrote:
> On Thu, November 5, 2009 08:47, Wu Fengguang wrote:
> > On Thu, Nov 05, 2009 at 08:46:55AM +0800, David wrote:
> >> Currently doing some testing with sticky stream id and format.
> >>
> >> Could you test the attached patch (applies to alsa git repo, without
> >> your patchset) and see if you get the initial 0.5s silence with your
> >> receiver?
> >
> > Yes it worked!
> 
> Worked as in you get no 0.5s of initial silence? Or worked as in you at
> least got some audio and the computer didn't crash? :)

no 0.5s :)

> > However something is broken when
> >
> > CONFIG_SND_HDA_POWER_SAVE=y
> > CONFIG_SND_HDA_POWER_SAVE_DEFAULT=1

In the above config, you need to restart playback within 1s to avoid
losing the first 0.5s samples. (Otherwise power save will kick in.)

> I was kind of expecting my patch to break both power save and
> suspend/resume given that it expects the stream format and id to survive
> from pcm_close to pcm_prepare (which they probably won't if power saving

Don't worry, I fixed that in my implementation :)

> and/or resume/suspend kicks in). Power save also seems to mess up some
> other parts of the driver even without my patch (haven't really looked
> into that yet...power save might be tricky with HDMI from what I've seen
> so far).

Yes, HDMI power save is inherently not possible given that the sink
devices have the more than 1s delays..

> The patch was just a test case to see if it was enough to fix the 0.5s
> silence on receivers which are less picky than mine (it still doesn't fix
> the 0.5s silence on my receiver but it fixes the
> silence-for-the-duration-of-a-track problem).
> 
> Next up, more testing with VCFG when I have more time. I have actually
> tried setting that bit but it didn't change anything. Comments in
> setup_dig_out_stream from hda_codec.c seems to suggest that it's a bit
> more complex than just setting the right bit.

No worry, I guess that's realtek specific problem (spdif_status_reset
is only set by it).

> > Attached is my updated patchset, which includes the sticky
> > stream/infoframe features.
> 
> Thanks, I'll take a look at it as soon as possible.

Thanks,
Fengguang