Yewwo
I am having issues getting HDMI audio working on my GTX 1080 Ti, so I'll run down the list of requested items to help you assist me in troubleshooting:
1) I've just recently (as in yesterday) upgraded from my GTX 780 OC to a brand spanking new EVGA 1080 Ti FTW3 Elite Gaming Black (try saying that three times fast!). Graphics-wise, everything's peachy. Audio-wise is another matter unfortunately. Previously, using the audio_cloverHDMI-130_v0.8.command file, I was able to get HDMI audio flawlessly on my GTX 780, without even needing an SSDT. I was even able to get it to coexist with the ALC898 on the motherboard by using the audio_cloverALC-130_v0.5.command shell script. But with the 1080 Ti, that is no longer the case.
Initially I thought "OK, somehow the bloody system "forgot" how to do HDMI audio. But upon running that shell script again, it said HDMI audio was already installed. I wasn't sure how that was possible since there were zero kext hotpatch entries for HDMI audio in my config.plist, and I've never used voodooHDA or any other "HDMI audio" kext. It just...
worked, all the way up to 7.1 (8 channel) 192 KHz.
What caught my attention was that the GTX 780 was registered as residing on the
PEG0 location, but the 1080 Ti is somehow on the
P0P2 location
even though it is in the same PCIe slot the GTX 780 was in. I have not changed any firmware, OS version, or even drivers as I already had the nVidia web drivers installed.
2) System Specs:
OS: macOS 10.12.6 (16G1314)
Motherboard: Gigabyte GA-Z87X-UD5H
BIOS Version: F7
CPU: i7-4770k (Non-OC'd, as OC is unstable with my sample, sadly)
GPU: nVidia GTX 1080 Ti (EVGA FTW3 Elite Gaming Black, model 11G-P4-6796-K2)
nVidia Web Driver version: 378.05.05.25f08
Cables tested: Monoprice 22 AWG HDMI cable, 15 ft., certified Cat2; Blue Jeans Cable Series 1, 15 ft., certified Cat2
Device path: GTX 1080 Ti -> Yamaha CX-A5100 -> Samsung UNH7150 TV
Amplifier used: Monoprice Monolith M7X, connected via XLR.
Note: Display tested directly connected to GPU in addition to the CX-A5100.
HDMI Modes tested: 1 and 2 (CX-A5100).
HDMI Processing on CX-A5100: Disabled - Set to "through"/passthrough mode. Monitor Check: Disabled to prevent CX-A5100 from overriding resolution based on EDID.
3) Guide used: This guide. Method: CloverHDMI
4) AppleHDA.kext version: 279.48
5-10) Attached and ready for viewing.
What's really piquing my curiosity here is the unusual switch from PEG0 to P0P2 while being in the same physical slot with no change to either firmware, OS, or drivers. I expect oddities coming from High Sierra, but Sierra shouldn't have been affected as it predates 10.13.
Any insight would be greatly appreciated. Hopefully we'll start figuring out just why Pascal GPUs have so much trouble with native HDMI audio.