I have an Audigy 2 ZS sound card connected via S/PDIF to a Logitech Z-680 decoder/speaker system. After upgrading ALSA userspace (alsa-headers, alsa-lib) to 1.0.9_rc2, all I got when trying to play DVD:s using AC3 passthrough was scratchy noises, and the external decoder indicated that it did not think it was getting AC3 data. Both Xine and MPlayer had this problem, and no amount of fiddling with ALSA settings would make it work. I am not running aRts, or any other sound server, and have no ~/.asoundrc file. Downgrading to ALSA userspace 1.0.8 made it work again. Reproducible: Always Steps to Reproduce: Portage 2.0.51.19 (default-linux/amd64/2005.0, gcc-3.4.3-20050110, glibc-2.3.4. 20050125-r1, 2.6.11-gentoo-r6 x86_64) ================================================================= System uname: 2.6.11-gentoo-r6 x86_64 AMD Athlon(tm) 64 Processor 3200+ Gentoo Base System version 1.6.10 Python: dev-lang/python-2.3.5 [2.3.5 (#1, Feb 18 2005, 12:57:44)] ccache version 2.4 [enabled] dev-lang/python: 2.3.5 sys-devel/autoconf: 2.59-r6, 2.13 sys-devel/automake: 1.7.9-r1, 1.8.5-r3, 1.5, 1.4_p6, 1.6.3, 1.9.5 sys-devel/binutils: 2.15.92.0.2-r8 sys-devel/libtool: 1.5.14 virtual/os-headers: 2.6.8.1-r4 ACCEPT_KEYWORDS="amd64 ~amd64" AUTOCLEAN="yes" CFLAGS="-march=athlon64 -O2 -pipe -fstack-protector -fweb -frename-registers - fomit-frame-pointer -momit-leaf-frame-pointer -funit-at-a-time -ftracer" CHOST="x86_64-pc-linux-gnu" CONFIG_PROTECT="/etc /usr/kde/2/share/config /usr/kde/3.4/env /usr/kde/3.4/ share/config /usr/kde/3.4/shutdown /usr/kde/3/share/config /usr/lib/X11/xkb / usr/share/config /usr/share/texmf/dvipdfm/config/ /usr/share/texmf/dvips/config/ /usr/share/texmf/tex/generic/config/ /usr/share/texmf/tex/platex/config/ /usr/ share/texmf/xdvi/ /var/qmail/control" CONFIG_PROTECT_MASK="/etc/gconf /etc/terminfo /etc/env.d" CXXFLAGS="-march=athlon64 -O2 -pipe -fstack-protector -fweb -frename-registers - fomit-frame-pointer -momit-leaf-frame-pointer -funit-at-a-time -ftracer" DISTDIR="/usr/portage/distfiles" FEATURES="autoaddcvs autoconfig ccache collision-protect distlocks sandbox strict userpriv usersandbox" GENTOO_MIRRORS="http://ftp.du.se/pub/os/gentoo http://gentoo.oregonstate.edu http://www.ibiblio.org/pub/Linux/distributions/gentoo" MAKEOPTS="-j2" PKGDIR="/usr/portage/packages" PORTAGE_TMPDIR="/var/tmp" PORTDIR="/usr/portage" PORTDIR_OVERLAY="/usr/local/portage" SYNC="rsync://makanee.ferretporn.se/gentoo-portage" USE="amd64 X Xaw3d a52 aalib acpi adns alsa bash-completion berkdb bitmap-fonts cdinstall cdparanoia cdr cjk crypt cscope curl doc dvd emacs emacs-w3 fam flac font-server freetype gcl gd gdbm gif glut gmp gtk gtk2 imagemagick imap imlib jp2 jpeg kde libwww lzw lzw-tiff mad maildir matroska mbox mikmod mp3 ncurses nls nocd nptl nptlonly nvidia offensive ogg oggvorbis openal opengl operanom2 pam perl pie png python qt readline ruby samba sdl sendfile slang spell sqlite ssl stencil-buffer tcpd tetex tiff truetype truetype-fonts type1-fonts unicode usb userlocales utf8 vorbis xface xine xml2 xmms xpm xrandr xv xvid xvmc zlib" Unset: ASFLAGS, CBUILD, CTARGET, LANG, LC_ALL, LDFLAGS, LINGUAS
Same problem here with an Audigy and a Logitech Z-5500 recently replaced from a Z-680 with which I had the same problem.
Pleasse report this upstream at http://bugtrack.alsa-project.org and let me know the bug number so I can track it.
https://bugtrack.alsa-project.org/alsa-bug/view.php?id=1069
