[Alsa-user] SPDIF stops working for AC3/DTS

[Ing. D. R. <da...@ro...>]

Hello,
   I am experiencing a strange problem after a motherboard upgrade.

   I could play stereo audio over SPDIF but the AC3 and DTS passtrough
works only after reboot - I am not sure when it stops working, but it
does not live longer than one day. However stereo still works. It is not
related to whenever I play stereo or ac3/dts content, after the reboot
everything works well.

   It's quite a bad behaviour, since I have to reboot my machine every
evening before playing a movie :/

   The board: Asus P5Q-E (HDA Intel / AD1989B)
   Kernel: does not matter (used 2.6.31 and 2.6.32), Gentoo
   Alsa: 1.0.21

   Are there any commands which can help to determine the source of the
issue?

   I am using an external decoder in speakers (Logitech Z5500) which
detect the stream type correctly (codec + channel count) but I have no
sound. The other speakers (Edirol MA15D) are producing a strange noise,
since the vendor probably forgot to mute compressed streams :) This 
noise is present in both working and non-working time and for me it is 
indistinguishable.

   When I was writing this email, I've tried to rmmod snd_hda_intel, 
then modprobe it, and the AC3/DTS worked again, without reboot. Any ideas?

   Thank you,

Daniel