No Bitstream audio with LSPCon - Works OK for Windows 10

The HDMI 2.0 output on my motherboard uses a Paradetech LSPCon. In Windows bitstream audio works fine with Kodi. With the Libreelec 11.0.4 though I get no sound at all with bitstream audio (PCM up to 7.1 works). Any tips on config changes I could try? (I am selecting the same working HDMI device for bitstream that I use for PCM).

On the plus side HDR switching is working nicely.

I've now tried on bare metal as well as with my VM and the behaviour is identical which means I can rule out the VM as being the cause. From what I have read most of these sorts of issues were solved 3-5 years ago in the kernel so I'm not sure if this is a general Linux/hardware issue or specific to Librelec.

Here is my dmesg from the VM:
[ 0.000000] Linux version 6.1.68 (sky42@jammy) (x86_64-libreelec-linux-gnu-gc - Pastebin.com

The issue is the same whether I use official 11.0.4 or the Sky42 build.

The Intel NUCs which use a Paradetech PS175 LSPCon seems to have a major firmware version of 7 (eg. 0x07_0x020) but my board seems to be on 0x08_0x2C.

Is there any more info I can provide to try to get some support with this?

chewitt Thanks for the response. I updated to the LE12 Nightly (19th Jan) and the problem remains the same. I only get basic vesa resolutions alot of the time and dmesg show some issues:

LibreELEC:~ # dmesg | grep i915
[    0.373362] i915 0000:00:02.0: [drm] VT-d active for gfx access
[    0.373483] i915 0000:00:02.0: vgaarb: deactivate vga console
[    0.373523] i915 0000:00:02.0: [drm] Using Transparent Hugepages
[    0.373529] i915 0000:00:02.0: [drm] *ERROR* Stolen reserved area [mem 0x8f700000-0xbe5fffff] outside stolen memory [mem 0xbc600000-0xbe5fffff]
[    0.439961] i915 0000:00:02.0: vgaarb: VGA decodes changed: olddecodes=io+mem,decodes=io+mem:owns=io+mem
[    0.440479] i915 0000:00:02.0: [drm] Finished loading DMC firmware i915/kbl_dmc_ver1_04.bin (v1.4)
[    1.294324] i915 0000:00:02.0: [drm] [ENCODER:94:DDI A/PHY A] failed to retrieve link info, disabling eDP
[    1.325912] [drm] Initialized i915 1.6.0 20201103 for 0000:00:02.0 on minor 0
[    1.400185] fbcon: i915drmfb (fb0) is primary device
[    1.757923] i915 0000:00:02.0: [drm] fb0: i915drmfb frame buffer device
[    4.958659] i915 0000:00:02.0: [drm] *ERROR* Link Xraining Unsuccessful

The EDID is for the correct device. Only the first displayport shows as connected which I believe is correct for LSPcon. The errors and end effect is the same if I use a VM or bare metal.

i915_display_info is here:
cat /sys/kernel/debug/dri/0/i915_display_infoCRTC info---------[CRTC:51:pi - Pastebin.com

The only thing that looks odd to me is it reporting HDCP 1.4 when the whole chain should support HDCP 2.X (Other than the completely wrong resolution table).

Are there any kernel switches I can use to increase the logging from i915?

Changed to a CAC-1088 external LSPCon and this works reliably but still no HBR audio in Linux. Any ideas on how to debug the audio side of HDMI in Linux?