I’m trying to get sound on an Asus PQ321Q 4K monitor through DisplayPort (GPU is GTX Titan). I’ve completed the troubleshooting instructions listed on ftp://download.nvidia.com/XFree86/gpu-hdmi-audio-document/gpu-hdmi-audio.html.
With DisplayPort SST, speaker-test seems to work randomly about 25% of the time. That is, if I leave it running, every time it starts testing a channel, there is about a 25% chance that I’ll hear pink noise out of that channel, and 75% that I’ll hear silence.
With DisplayPort MST, /proc/asound/card1/eld* all have “monitor_present 0” and “eld_valid 0”.