- Nov 11, 2018
- Asus Z690 ProArt Creator
- RX 6800 XT
- Classic Mac
- Mobile Phone
I have a strange question that perhaps you (or another) could answer:
I have discovered that my system REQUIRES VT-d to be enabled to get a BlackMagic Decklink card to properly work for AVID Media Composer. If I disable VT-d, AVID doesn't like to fully launch (due to the BM driver). I have a Sapphire Vega 64 in slot 1, the BM card in slot 2, and a Myricom 10gigE fibre card in the bottom slot, with an Inland Premium m2 (I know, not the best) occupying the M2M slot. My BIOS is set for "PCH side" for the PCI-4 slot.
This system (Designare z390, 9900k, Bios F9i, OC 073, Catalina 10.15.7) has been terrific for quite some time (thanks to you and this thread) as well as two other similar builds. There doesn't appear to be any ill-affects of keeping it on (I discovered this workaround well over a year ago) but I guess I'm confused as to why. The BM driver works fine for other softwares (Resolve, Adobe) so one could say this is a software bug for the BM AVX plugin for AVID specifically, but it is strange how enabling VT-d seems to rectify.
The BM card is SUPPOSED to be 4, 8 and 16 lane compatible, so I guess I can try switching the BM card with the Myricom card again (thought I did that long ago) to see if VT-d is no longer required...but if you or anyone else had a thought as to why VT-d solves the problem that would be swell.
Thanks as always,
Another well-described problem statement with all the right background information!
There is in fact a very short answer to your “strange question”, as follows:
- VT-d is a good thing. All real Macs have VT-d enabled and if you use the latest OpenCore EFI from this thread, it will enable it fully such that AppleVTD will appear in IORegistryExplorer.
- AppleVTD is also necessary to connect Apple’s own Thunderbolt-to-Gigabit Ethernet adapter.
- AppleVTD also makes it possible to connect Antelope Audio Thunderbolt devices.
- If the BlackMagic Decklink requires VT-d (and “AppleVTD”) then it is not a problem. We are supposed to have VT-d (in BIOS) and AppleVTD (in IOReg) enabled.