no 5.1 surround through hdmi

[tedrampart]

I don't seem to have the option of selecting 5.1 audio with hdmi out. I only have stereo even though my system is supposed to support it.

I can play 2 channels no problem but thats it. I'd like to know how to get 5.1 to play through the hdmi.

currently running 11.04 64bit, on an acer 1810t
sound module: snd-hda-intel

I've tried a few things already but they've either rendered all sound gone, or only the front left and right channels play..

anyone have any suggestions?

[tedrampart]

bump,,, anyone?

[pkt1153]

I have the same problem, and I think, at least in my case, it may be related to the EDID/ELD data that is reported to the ALSA sound drivers by the NVidia chipset.

I have an NVidia based (Gigagbyte 8400GS) video card with HDMI out. The card communicates with my LCD TV, which reports that it only support 2 channel (2 speaker) capability. I believe this is forcing the ALSA driver to only allow 2 channel sound (2 channel stereo PCM) output on the HDMI interface. I haven't found a way to override the ELD file so that the driver will allow 6 (5.1) or 8 (7.1) channel output even though the chipset supports those modes. I've run across some cryptic (to me anyway) developer emails on the ALSA development page about a possible bug in the ALSA drivers that won't allow an override in the EDID/ELD data.
In my case, I have an HDMI switch between my computer and TV that can extract AC3 data and spit it out on an optical TOSLINK to my surround sound receiver. Unfortunately with this setup, my video card/sound driver chipset cannot "see" my surround sound receiver to construct a proper ELD for it.

I'm not sure if you have tried the command

speaker-test -D[device name] -c6

I can only get it to work with the -c2 option. The -c6 option gives me an error that the number of channels is not supported.

I'm not sure if this helps or not, but it may give you another option to explore as to the cause of the 2 channel stereo restriction you are seeing.