Bug 101222

Summary: [amd-staging] No DisplayPort surround sound with DC on RX 480 (HDMI works)
Product: DRI Reporter: James Le Cuirot <chewi>
Component: DRM/AMDgpuAssignee: Default DRI bug account <dri-devel>
Status: RESOLVED MOVED QA Contact:
Severity: normal    
Priority: medium CC: fdsfgs, harry.wentland, russianneuromancer
Version: XOrg git   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
/proc/asound/HDMI/codec#0
none
/proc/asound/HDMI/eld#0.0
none
/proc/asound/HDMI/eld#0.1
none
Some interesting dmesg output
none
fix none

Description James Le Cuirot 2017-05-28 21:11:20 UTC
Created attachment 131555 [details]
/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!
Comment 1 James Le Cuirot 2017-05-28 21:11:54 UTC
Created attachment 131556 [details]
/proc/asound/HDMI/eld#0.0
Comment 2 James Le Cuirot 2017-05-28 21:12:10 UTC
Created attachment 131557 [details]
/proc/asound/HDMI/eld#0.1
Comment 3 James Le Cuirot 2017-05-28 21:16:24 UTC
Created attachment 131558 [details]
Some interesting dmesg output
Comment 4 Mikko Autio 2017-06-22 15:08:51 UTC
Created attachment 132140 [details] [review]
fix

Attached patch fixes multi-channel HDMI audio on my RX 460.
Comment 5 Harry Wentland 2017-06-22 15:30:19 UTC
Thanks, Mikko. Looks good. Do you want to send a patch to amd-gfx? If not I'll create a patch with description and title for it.
Comment 6 James Le Cuirot 2017-06-22 21:29:50 UTC
(In reply to Mikko Autio from comment #4)
> Attached patch fixes multi-channel HDMI audio on my RX 460.

I was about to shower you with praise but sadly that patch made no difference here. :(
Comment 7 Mikko Autio 2017-06-23 03:02:04 UTC
(In reply to James Le Cuirot from comment #6)
> (In reply to Mikko Autio from comment #4)
> > Attached patch fixes multi-channel HDMI audio on my RX 460.
> 
> I was about to shower you with praise but sadly that patch made no
> difference here. :(

Maybe there is something else broken with DisplayPort audio?

I have my receiver plugged into HDMI port of my RX 460 and my TV is plugged into my receiver. Multi-channel audio over HDMI was working fine even without the patch (including AC3/DTS pass-through), but only up to 5.1 channels. Anything over 5.1 channels appeared as stereo on my receiver.

With the patch 7.1 LPCM and DTS-HD/TrueHD pass-through are now working fine.
Comment 8 Mikko Autio 2017-06-23 03:03:03 UTC
(In reply to Harry Wentland from comment #5)
> Thanks, Mikko. Looks good. Do you want to send a patch to amd-gfx? If not
> I'll create a patch with description and title for it.

I'll let you think of a description and title for it ;)
Comment 9 James Le Cuirot 2017-06-23 21:00:40 UTC
(In reply to Mikko Autio from comment #7)
> (In reply to James Le Cuirot from comment #6)
> > (In reply to Mikko Autio from comment #4)
> > > Attached patch fixes multi-channel HDMI audio on my RX 460.
> > 
> > I was about to shower you with praise but sadly that patch made no
> > difference here. :(
> 
> Maybe there is something else broken with DisplayPort audio?

Yes! I switched the outputs around (one was just using an adapter) and now it works! I really should have tried that sooner. This arrangement is fine for me as the monitor is just stereo anyway.

LPCM works and so does ALSA pass-through but PulseAudio is refusing to do pass-through for some reason. I've had it working in the past but I can live with that for now.
Comment 10 Martin Peres 2019-11-19 08:18:13 UTC
-- GitLab Migration Automatic Message --

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