[ALSA - driver 0002159]: ac3 passthrough not working on recent versions

bugtrack
2006-06-16T11:37:14Z

Last Modified: 06-16-2006 13:37 CEST
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Summary: ac3 passthrough not working on recent versions
Description:
Using the following AC3 passthrough with mplayer works:
Linux 2.4.31
alsa-driver 1.0.8-7 (debian stable packaged)

Using Linux 2.6.15 (both with alsa-driver 1.10rc3 that ships with the
kernel and
alsa-driver 1.0.11) it doesn't work. The reciever just says "unlock" and
stays quiet.

The only change is booting with different kernels, no other config or
hardware is touched, so this must be a driver regression.

The card is YMF-754 based, connected with coax spdif to my HK reciever.

If you need more info, just tell me and I'll dig it up.
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Raymond - 06-16-06 13:31
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Are you really sure that the patch "ymfpci: add per-voice volume controls"
break AC3 passthrough, the purpose of that patch is to implement pcm
volume control per substream using the hardware mixing of ymfpci

Please note that STAC9708 has no SPDIF control registers, there is no need
to compare ac97 registers

You should compare those ymfpci register

cat /proc/asound/card0/ymfpci

iecset

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Mimosius - 06-16-06 13:37
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Hi Raymond,

yes, I'm really sure this patch breaks AC3 passthrough. A comparison of
the /proc/asound/card0/ymfpci registers against 1.0.9b (patched up to
1.0.11 without Clemens patch) and 1.0.11 (native) is included in my
previous note.