[colonpowell]

I have an ASUS M3N78-VM running Ubuntu (9.10). I can't get any audio (or light) to come from the optical output on the back panel of the motherboard. I have audio playing just fine through the mini plug output. In Ubuntu I can select Digital iec958 out, and nothing is muted as far as I can tell, but I don't get any sound.


I've searched on google and found some old posts that unfortunately didn't help. Does anyone have experience with getting this to work?

 

[bac522]

From a shell window what is the results of "aplay -l"?


Essentially, ALSA defaults to the analog port and you have to create a .asoundrc file to point to the digital port.

 

[colonpowell]

aplay -l shows a digital port, but apparently it's only for the internal header, not the optical output on the back panel. (soundtest doesn't play anything when I direct it to that digital port). I've checked alsamixer and nothing is muted. It seems like alsa is only picking up the internal header and isn't seeing the optical output.


I wonder if updating to a newer alsa version will help? I'm not sure how to do that though, I tried to download the newest alsa driver and alsa kernel, but just got a bunch of compiler errors (using hgcompile).

 

[k_ross]

It seems this is a known problem.

https://bugtrack.alsa-project.org/al...ew.php?id=4330


At the end of the comments one person recommends a $3 part that can be hooked up to the internal header to give you optical output.

 

[colonpowell]

Thanks -- looks like I'll have to go that route then.

 

[bac522]

I don't know if I buy the alsa bug...I can't actually see the bug because it requires a login and I really doubt that ASUS would have built two separate SPDIF interfaces on the MB. I'd still like to see the print out from aplay -l.

 

[colonpowell]

Hi Bac522, here's the aplay -l listing:


**** List of PLAYBACK Hardware Devices ****

card 0: NVidia [HDA NVidia], device 0: VT1708B Analog [VT1708B Analog]

Subdevices: 2/2

Subdevice #0: subdevice #0

Subdevice #1: subdevice #1

card 0: NVidia [HDA NVidia], device 1: VT1708B Digital [VT1708B Digital]

Subdevices: 1/1

Subdevice #0: subdevice #0

card 0: NVidia [HDA NVidia], device 3: NVIDIA HDMI [NVIDIA HDMI]

Subdevices: 1/1

Subdevice #0: subdevice #0


Using device 1 in soundtest or anything I can find doesn't make any sound, there's no light ever coming out of the port. There's an option in the sound tray icon for the digital out as well, but nothing makes sound.


From what I've read part of the bug is that alsa thinks the optical out on the back of the motherboard is somehow a digital input, but I'm not sure how to verify or change that.

 

[bac522]

Well, not seeing the light out of the TOS port might be an issue, but maybe it only lights up when sound is active. Sure there isn't a BIOS setting for it?


But try the following in an .asoundrc file in your home directory.

Code:

pcm.spacespdifdmix {
        type dmix
        ipc_key 83484784
        slave {
                pcm "hw:0,1"
                format S32_LE
                rate 44100
        }
}

pcm.spacespdif {
        type plug
        slave {
                pcm spacespdifdmix
        }
}

pcm.!default {
        type plug
        slave {
                pcm spacespdifdmix
        }
}

 

[colonpowell]

Finally got a chance to try it, but no joy. I think I'll work on figuring out how to connect the internal header to the optical cable.

 

[eb50]

im having teh same issue as well. let me konw if you fixed it

 

[colonpowell]

I think that output is unusable in linux -- you'll have to tap into the internal one to get digital out. I'm using the HDMI out right now, but when I get my stereo back I'll have to switch back to the analog out.

 

[Servicetech571]

I have the same board on my HTPC. This is one of many issues that switched me to Windows 7. As much as I love Ubuntu 10.10 for my desktop I found Windows 7 to be much easier to use for HTPC.

 

[indubitable]

Hi, I have this board as well and dealt with the same problems under Linux. My eventual solution was to purchase the SPDIF bracket that ASUS sold separately and connect it to the SPDIF header at the edge of the board. It's a four-pin connector with coax and Toslink outputs on the bracket, available from a few places online for about $15 + shipping. Works like a charm for me, required no additional setup under Mythbuntu 10.04, just make sure you have the IEC958 outputs unmuted in ALSA using alsamixer or the like.