No HDMI Audio in Clamshell Mode

[Gustavo Martins]

Can't make HDMI sound work in clamshell mode.

Basically, if I connect the HDMI cable after booting the system everything works fine with external display (Samsung 4k 43”) as sound output. However, if I boot in clamshell mode (with the lid closed) the video starts as soon as the apple logo appears, but no sound (ps.: the internal speakers works fine in this case); furthermore, the external display doest not appear in sound output option, the only way to make it work is disconnecting and connecting the HDMI cable, so the monitor appears in sound output list.

Other way to make it work is putting the laptop to sleep and then waking it up.

I’ve already (i) tested in BigSur, Ventura and Sonoma; (ii) updated WhateverGreen, AppleALC and Lilu; (ii) applied some framebuffer patches following OC-Little-Translated Guide (iGPU_DeviceProperties.md),  WhateverGreen Guide (FAQ.IntelHD.en.md) and Dortania Post Install BusID Patching Guide; and (iv) generated the framebuffer patch with Hackintool.

All of them with no luck.

Any ideas? Thanks in advance.

Laptop Dell - SMBIOS MacBookPro14,1
Currently using BigSur 11.7.10
Processor: i5-7200U
Graphics: Intel HD 620 (no dGPU)
Audio: Realtek ALC256 (ALC3246)
AAPL,ig-platform-id: 00001659
boot-args: -v debug=0x100 alcid=21 watchdog=0 igfxonln=1 -vi2c-force-polling

config.plist.zip