Created attachment 134990 [details]
dmesg output filtered to show drm messages
When using a DC-patched kernel (the drm-next-4.15-dc branch to be specific), HDMI audio output on RX Vega does not work, as the device(s) are simply listed as unconnected.
Audio over DisplayPort works, but the second device (A 5.1 Surround Sound AV Receiver) does not register as an audio-output.
It doesn't matter which port is used; All 4 physical monitor outputs (3 DisplayPorts, 1 HDMI), when connected to another device, be it the AV receiver or the monitor, fails to register any audio outputs. Only DisplayPort->DisplayPort works.
The attached dmesg log file shows both devices being connected and detected as audio outputs by drm, including the number of configurations available on each.
Created attachment 134991 [details]
Parsed edid output for the receiver.
Created attachment 134992 [details]
Parsed edid output for the monitor, connected via DP.
Created attachment 134993 [details]
I have exactly the same problem here with a rx vega 56 and rx vega 64
It looks like we missed this when bringing up Vega. We got a patch in the works. It should land sometime this week.
Thank you for your quick response, I am glad to hear that a patch will be there soon
Created attachment 135191 [details] [review]
[PATCH 1/2] drm/amd: Add DCE12 resource strap registers
Created attachment 135192 [details] [review]
[PATCH 2/2] drm/amd/display: Read resource_straps from registers for DCE12
@randomsalad, I've attached the patches. Please let me know if they resolve the issue.
Created attachment 135197 [details]
Compilation error for the patch
The proposed patch doesn't compile when applied to an otherwise clean version of drm-next-4.15-dc (commit id 9b38bd1b8f5c874c3d1f330e0dcf4e7d84137477 at time of writing). Does it rely on other changes present on the WIP branch? I've attached the compilation errors.
Whoops, seems I blundered and didn't see there was not one, but two different patch files.
The compilation succeeds now, will proceed to testing it.
I can confirm the patch works, and was the only thing missing to get HDMI audio working on my Vega card. I can confirm it works for atleast 5.1 and 2.0 channel audio as those are the only options available to me with my Receiver, though this was just what I needed.
Thanks for the confirmation, marking this as resolved.