Force display output to DP with audio on HDMI

fezster · January 15, 2024 at 12:58 PM

I have a Optiplex 3050 which has both a DisplayPort 1.2 (capable of 4k) and HDMI 1.4 (capable of 1080p only).

I'm using LibreElec 11 stable (although tried 12 nightly too) and I cannot get HD audio to work on the DP using a Benfei DP->HDMI adapter (reading around, seems to be a common problem with NUC's as well). DD/DTS work fine.

I can, however, get HD audio working over the HDMI 1.4 connection.

So I want to utilize both connections simultaneously but, despite trying for a few days, whenever I connect the HDMI 1.4 cable, Kodi always output's it's display on that port rather than the DP:

Code

LibreELEC:~ # tail /sys/class/drm/*/status
==> /sys/class/drm/card0-DP-1/status <==
connected

==> /sys/class/drm/card0-DP-2/status <==
disconnected

==> /sys/class/drm/card0-DP-3/status <==
disconnected

==> /sys/class/drm/card0-HDMI-A-1/status <==
connected

==> /sys/class/drm/card0-HDMI-A-2/status <==
disconnected

==> /sys/class/drm/card0-HDMI-A-3/status <==
disconnected

Display More

Kodi log shows:

Code

2024-01-15 11:34:25.035 T:876      info <general>: CDRMUtils::FindConnector - using connector: HDMI-A-1

I tried adding the following to syslinux.cfg, but nothing changed:

Code

APPEND boot=UUID=1101-5649 disk=UUID=d8c7d193-fa09-4fcd-b27b-41b739035d2d portable quiet initrd=/edid.cpio drm.edid_firmware=edid/edid.bin video=DP-1:D

If I remove the HDMI-A-1 in syslinux:

Code

APPEND boot=UUID=1101-5649 disk=UUID=d8c7d193-fa09-4fcd-b27b-41b739035d2d portable quiet initrd=/edid.cpio drm.edid_firmware=edid/edid.bin video=HDMI-A-1:d video=DP-1:D

then Kodi starts on the DisplayPort, but the HDMI-A-1 is disabled and so does not output any audio (it also shows as disconnected under /sys/class/drm/card0-HDMI-A-1/status

Is there any way to force Kodi to use the DP connection, whilst still allowing the HDMI for audio?

**chewitt** · January 15, 2024 at 1:09 PM

I'm not sure if adding "video=DP-1:1920x1080M@60" will result in DRM (and thus Kodi) preferring DP-1 output over HDMI-A-1 or will simply force that output to 1080p and not change anything. It's a cheap trick to try though.

fezster · January 15, 2024 at 2:05 PM

Thanks for the suggestion, but same thing:

Code

APPEND boot=UUID=1101-5649 disk=UUID=d8c7d193-fa09-4fcd-b27b-41b739035d2d portable quiet initrd=/edid.cpio drm.edid_firmware=edid/edid.bin video=DP-1:1920x1080M@60

Code

2024-01-15 13:14:47.180 T:877      info <general>: CDRMUtils::FindConnector - using connector: HDMI-A-1

**chewitt** · January 16, 2024 at 9:59 AM

Code

<advancedsettings>
	<videoscreen>
		<monitor>Generic PnP Monitor #1</monitor>
	</videoscreen>
</advancedsettings>

^ that content goes in /storage/.kodi/userdata/advancedsettings.xml (from https://forum.kodi.tv/showthread.php?tid=363060) but I have no idea what to replace "Generic PnP Monitor #1" with. Perhaps "HDMI-A-1" or have a look in kodi.log for the m_deviceName and m_displayName values logged for audio cards as I have a hunch it'll be based on EDID data.

fezster · January 16, 2024 at 1:16 PM

Code

<advancedsettings>
        <videoscreen>
                <monitor>DP-1</monitor>
        </videoscreen>
</advancedsettings>

Thanks! That definitely forced it to use DP.

However, it then it fails to load the GUI with this error:

Code

2024-01-16 13:11:35.278 T:758     debug <general>: OnLostDevice - notify display change event
2024-01-16 13:11:35.278 T:758     debug <general>: CDRMUtils::SetMode - found crtc mode: 1920x1080 @ 60 Hz
2024-01-16 13:11:35.278 T:758      info <general>: GLES: Maximum texture width: 16384
2024-01-16 13:11:35.278 T:758     debug <general>: guilib: Fill viewport on change for solving rendering passes
2024-01-16 13:11:35.322 T:758     debug <general>: ffmpeg[0x0]: [image2] Custom AVIOContext makes no sense and will be ignored with AVFMT_NOFILE format.
2024-01-16 13:11:35.445 T:758     debug <general>: EGL Debugging:
                                                   Error: EGL_BAD_SURFACE
                                                   Command: eglSwapBuffers
                                                   Type: EGL_DEBUG_MSG_ERROR_KHR
                                                   Message: dri2_swap_buffers
2024-01-16 13:11:35.446 T:758     debug <general>: CDRMUtils::DrmFbGetFromBo - using modifier: INTEL_X_TILED
2024-01-16 13:11:35.446 T:758     debug <general>: CDRMAtomic::FlipPage - Execute modeset at next commit
2024-01-16 13:11:35.446 T:758     error <general>: CDRMAtomic::DrmAtomicCommit - test commit failed: (Invalid argument) - falling back to last successful atomic request

2024-01-16 13:11:35.446 T:758     debug <general>: CDRMAtomicRequest::LogAtomicDiff - DRM Atomic Request Diff:
2024-01-16 13:11:35.446 T:758     error <general>:
                                                   Object: plane        ID: 31
                                                   Object: plane        ID: 52
                                                   Object: plane        ID: 73
                                                   Object: connector    ID: 104
                                                   Object: plane        ID: 39
                                                   Object: plane        ID: 81
                                                   Object: plane        ID: 89
                                                   Object: plane        ID: 47
                                                   Object: plane        ID: 60
                                                   Object: plane        ID: 68
                                                   Object: crtc ID: 51
                                                   Object: crtc ID: 72
2024-01-16 13:11:35.446 T:758     error <general>: CDRMAtomic::DrmAtomicCommit - atomic commit failed: Invalid argument
2024-01-16 13:11:35.446 T:758     debug <general>: CWinSystemGbmGLESContext::PresentRender - Sending display reset to all clients

Display More

I tried ensuring the resolution I'm using is supported by both outputs (i.e. providing the following flags in syslinux.cfg):

Code

APPEND boot=UUID=10B4-4A77 disk=UUID=93786be3-5652-47ab-b200-e2f498d33733  quiet video=DP-1:1920x1080M@60 video=HDMI-A-1:1920x1080M@60

**chewitt** · January 17, 2024 at 2:12 PM

Hmm.. honestly no clue, but I'll sleep on it and see what that inspires (or not)

**Da Flex** · January 17, 2024 at 4:09 PM

Probably an (LS)PCON chip issue:

Post

RE: Time to upgrade my NUC. What's hot today?

[…]

As you can see on this block diagram, NUC11PAxxx does not have a native HDMI port. It is using a DP->HDMI protocol converter (PCON) chip. It is more than likely the source of your audio passthrough issues. So this is not a gen11 issue but an issue specific to that NUC model. There is nothing to fix from LE/Kodi side.

smp

January 15, 2024 at 2:36 AM

PS: Guys, please do me favor, and stop those double posts:

Thread

HD Audio from DisplayPort - no sound (HDMI works)

Related thread: Force display output to DP with audio on HDMI where I am trying to use the HDMI for sound and DP for video.

I wanted to dig deeper into why the DP 1.2 on my Optiplex 3050 is not able to play HD audio. I've made some progress (I think!) but I'm stuck on where to go from here. If it is a limitation of the DP itself, I'd like to understand why.

Here's my findings:

HD Audio (TrueHD and DTS HD MA) from HDMI 1.4 works - log here:

(Code, 79 lines)

HD Audio (TrueHD and DTS HD MA) from DP 1.2…

fezster

January 16, 2024 at 11:37 AM

fezster · January 17, 2024 at 9:05 PM

I suspected as much. Just seemed odd that 7.1 LPCM works fine (but not HD audio bitstreams).

FYI - the other post was more focused on trying to fix the HD Audio, whereas this one was on utilizing 2 x display outputs. That's why I started a new thread.

Force display output to DP with audio on HDMI

RE: Time to upgrade my NUC. What's hot today?

HD Audio from DisplayPort - no sound (HDMI works)

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