[amd-staging] No DisplayPort surround sound with DC on RX 480 (HDMI works)

Submitted by James Le Cuirot @chewi

Assigned to Default DRI bug account

Link to original bug (#101222)

Description

Created attachment 131555
/proc/asound/HDMI/codec#0

I've been trying amd-staging on and off for a while in the hope of getting HDMI/DP surround sound working. There seems to be very few people trying amd-staging and even fewer trying surround sound as I haven't seen a single mention of it anywhere. Is it even supposed to work yet?

Stereo output is working but multi-channel LPCM only appears on my receiver as stereo and AC3 pass-through doesn't work at all. I had all this working on the same system with my old HD 4670 and I've made do with S/PDIF from my on-board sound in the meantime. I've tried directly with ALSA and via PulseAudio.

The latest kernel I've tried is 4.11 with b382281b45ec359deeeeef715b182322f4fa9566. I've found alsa-lib and friends can make a difference in the past so I just tried 1.1.4.

I'll attach some details. Note that I have a stereo monitor plugged into the HDMI port and my receiver in the first DisplayPort. I obviously select the right output when testing!

Attachment 131555, "/proc/asound/HDMI/codec#0":
codec_0