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

bugtrack
2006-06-19T19:43:30Z

The following issue has been REOPENED.
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<https://bugtrack.alsa-project.org/alsa-bug/view.php?id=2159>
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Reported By: nikke
Assigned To: Clemens Ladisch
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Project: ALSA - driver
Issue ID: 2159
Category: PCI - ymfpci
Reproducibility: always
Severity: minor
Priority: normal
Status: feedback
Distribution: Debian
Kernel Version: 2.6.15
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Date Submitted: 05-24-2006 23:44 CEST
Last Modified: 06-19-2006 21:43 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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Clemens Ladisch - 06-19-06 13:33
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My patch indeed broke AC3 passthrough. However, it fixed the incorrect
channel routing of the rear analog output.

The problem of the swapped rear channels is a bug in either the hardware
or in the firmware Yamaha provided to us, so the driver has to work around
it by swapping the rear channels before playing them. The rear channels
are a resource shared between the rear analog output and the digital
output, so the channel swapping workaround affects both outputs (although
the bug itself affects only the analog output).

A later patch added the rear_swap module option so that the user can
choose which one of the outputs is right. Use "rear_swap=1" to get
correct AC3 output.
(This module option probably should be a mixer option.)

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nikke - 06-19-06 21:43
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Euh. Now I'm confused.

My interpretion of the docs are that default options in 1.0.11 are to do
output so AC3 works. This seems like a sane behaviour to me, since AC3 has
worked before and there are probably more users of AC3 surround than
analog output surround.

Also, I have tried 1.0.11 both with rear_swap=0 and =1
(using modprobe snd-ymfpci rear_swap=X)
and neither works.

Am I missing something obvious?

Issue History
Date Modified Username Field Change
======================================================================
05-24-06 23:44 nikke New Issue
05-24-06 23:44 nikke Distribution => Debian
05-24-06 23:44 nikke Kernel Version => 2.6.15
05-24-06 23:47 nikke Issue Monitored: nikke
06-02-06 04:23 Raymond Note Added: 0010045
06-02-06 04:25 Raymond Note Edited: 0010045
06-12-06 13:14 Mimosius Issue Monitored: Mimosius
06-14-06 22:32 nikke Note Added: 0010216
06-15-06 02:18 Raymond Note Added: 0010221
06-15-06 02:27 Raymond Note Edited: 0010221
06-15-06 11:03 Mimosius Note Added: 0010237
06-15-06 23:43 nikke Note Added: 0010246
06-16-06 13:01 Mimosius Note Added: 0010250
06-16-06 13:16 Mimosius Note Edited: 0010250
06-16-06 13:26 Raymond Note Added: 0010251
06-16-06 13:31 Raymond Note Edited: 0010251
06-16-06 13:37 Mimosius Note Added: 0010252
06-16-06 16:25 Raymond Note Added: 0010255
06-17-06 01:17 nikke Note Added: 0010262
06-17-06 02:43 Raymond Note Edited: 0010251
06-17-06 10:21 Raymond Note Added: 0010266
06-17-06 10:24 Raymond Note Edited: 0010266
06-17-06 11:02 Raymond Note Added: 0010267
06-17-06 14:25 Raymond Note Added: 0010268
06-17-06 15:16 nikke Note Added: 0010269
06-17-06 16:10 Raymond Note Added: 0010270
06-17-06 16:23 Raymond Note Edited: 0010270
06-17-06 18:22 rlrevell Note Added: 0010280
06-18-06 04:03 Raymond Note Added: 0010295
06-18-06 04:08 Raymond Note Edited: 0010295
06-18-06 04:14 Raymond Note Edited: 0010295
06-18-06 13:30 Raymond Note Edited: 0010295
06-19-06 13:11 Clemens LadischStatus new => assigned
06-19-06 13:11 Clemens LadischAssigned To => Clemens Ladisch
06-19-06 13:33 Clemens LadischStatus assigned => resolved
06-19-06 13:33 Clemens LadischResolution open => not fixable
06-19-06 13:33 Clemens LadischNote Added: 0010307
06-19-06 21:43 nikke Status resolved => feedback
06-19-06 21:43 nikke Resolution not fixable => reopened
06-19-06 21:43 nikke Note Added: 0010320
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