[pulseaudio-discuss] IEC958 on USB Sound Blaster issue
tanu.kaskinen at linux.intel.com
Fri Feb 7 06:46:41 PST 2014
On Wed, 2014-01-29 at 14:23 +0100, Richard Körber wrote:
> I think just found an issue with PulseAudio. I'd like to discuss it here
> before I open a bug, because I'm not sure if it is really an issue.
> My goal is to connect my notebook to a 5.1 surround amplifier via SPDIF.
> For that purpose I have bought a Creative USB Sound Blaster X-Fi HD. It
> was a good choice for the features I need.
> The X-Fi HD works almost plug-and-play. When I connected it via USB, it
> was immediately detected by PulseAudio. Even the volume knob worked out
> of the box. My amplifier also detected a signal on the SPDIF line, and I
> selected the IEC958 port in pavucontrol. However, I could not play
> anything. The sound was just muted regardless of all the pavucontrol
> settings I tried.
> I searched the web and found other people having the same issue, and
> also one solution. It seems that the SPDIF output is a different
> hardware device. 
> In the /etc/pulse/system.pa I added this line:
> load-module module-alsa-sink device=hw:0,1
> After a restart, I was finally able to hear sound!
> However, the SPDIF output is now shown as a separate Output Device in
> pavucontrol. It also does not offer the "Advanced" options for setting
> AC3 and DTS. (According to the ALSA vendor matrix, the X-Fi HD SPDIF
> output supports AC3 and DTS.)
> The IEC958 port of the original X-Fi HD device is still shown and still
> Now I wonder... Shouldn't PulseAudio detect and map the hw:0,1 device to
> the IEC958 port, so the system.pa tweak is not necessary?
No, alsa should map the iec958:0 device (which pulseaudio uses for
spdif) to hw:0,1. This appears to be an alsa bug.
More information about the pulseaudio-discuss