Open Radar

 
macOS High Sierra now allows attaching external GPUs (eGPU) and Apple seems to have started an effort to allow using VR on the Mac. I have recently bought the External Graphics Development Kit and intend to develop VR experiences for Mac users. However, currently the development tooling and content one can test with are extremely limited and SteamVR for Mac is still extremely unstable.

Therefore, as a developer, I'd would much appreciate if there would be a way to enable the eGPU under Boot Camp to allow switching to Windows based development and test environment in some cases.

If I currently connect the eGPU to my MacBook Pro (13-inch, 2016) running macOS 10.13.2 (17C88) and try to boot into Windows 10 via Boot Camp, the boot just freezes. 

Steps to Reproduce:
1) Install Windows 10 via Boot Camp on a Mac
2) Attach an eGPU via Thunderbolt 3 (I used the official External Graphics Development Kit with Radeon RX 580 8 GB)
3) Install the drivers for the eGPU and the video card in Windows
4) Reboot the Mac back into Windows via Bootcamp

Expected Results:
The Mac will successfully boot into Windows via Boot Camp and the eGPU will be recognized and usable.

Observed Results:
If the eGPU is plugged into the Mac when Windows is booting via Boot Camp, the Mac will hang and will need to be force-restarted.

If the eGPU is plugged into the Mac once Windows has finished loading, it will appear in the Windows Device Manager list, but will be reporting 'Error Code 12' in that the necessary system resources were unable to be allocated to it.

Environment:
- macOS Sierra 10.13.2
- Boot Camp
- Windows 10 Pro N (1709)
- Radeon RX 580 8 GB in a Sonnet external GPU chassis with Thunderbolt 3