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

David Härdeman david at hardeman.nu
Thu Oct 29 09:16:21 CET 2009

On Wed, October 28, 2009 05:46, Wu Fengguang wrote:
> - the checksum field cannot be removed - otherwise 8-channel audio
>   will be played only as 2-channel.
> - if add a 800ms sleep in intel_hdmi_playback_pcm_prepare(), the
>   first-0.5s-samples-lost problem disappears
> Attached is the updated patchset.

Good morning,

I tried your latest patchset (2009-10-28) on top of 2.6.32-rc5.

The first problem I came across was that in these lines from

	if (spec->sink_present[i] != true)

spec->sink_present[i] was always false for some reason (is sink_present
only set as a result of HDMI hot-plug detection?) so I commented out those
two lines for now.

However, I still have the silence (on track change) problem.

If the msleep() you suggested fixes the silence during the first 0.5s
problem, then perhaps it would be possible to change the infoframe code so
that an audio infoframe with the ct bits set to zero is transmitted when
the pcm device is not in use instead of using a sticky infoframe (which
seems to fix it for me at least)?

Also, are you sure that the checksum is really supposed to be in the DIP
buffer? The buffer hardware size seems odd if that is the case (since PB10
will have to be discarded). Section of HDA034-A2 and HDA036-A
(which you referred to) both seem to suggest that the checksum byte should
be excluded (which would make the hardware and software buffer sizes
match). Could you perhaps get clarification on that point from someone at


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