THE ISSUE
During the setup and installation of your eGFX solution, it can happen that Thunderbolt connectivity is being blocked which in turn causes both the Barco Display Controller and your eGFX solution to be blocked. You may receive (but not always) this Device Manager error message "(Code 55)" or "(Code 12)", which indicates that the device is blocked from enumeration to protect from DMA attacks. In Layman's terms that would mean that it is the Kernel DMA Protection affecting the Thunderbolt connectivity.
You are experiencing this issue due to running the BitLocker and The Kernel DMA Protection at the same time on your workstation. In this Microsoft article, it states that there can be an incompatibility between the BitLocker and The Kernel DMA Protection. You will find the explanation in the beforementioned article in the Note under System compatibility as a reference to the Kernel DMA Protection and BitLocker DMA countermeasures.
BACKGROUND on KERNEL DMA PROTECTION
In Windows 10 version 1803, Microsoft introduced a new feature called Kernel DMA Protection to protect PCs against drive-by Direct Memory Access (DMA) attacks using PCI hotplug devices connected to externally accessible PCIe ports (e.g., Thunderbolt™ 3 ports and CFexpress). In Windows 10 version 1903, Microsoft expanded the Kernel DMA Protection support to cover internal PCIe ports (e.g., M.2 slots)
You can find the background and more details on Kernel DMA protection here.
For Thunderbolt DMA protection on earlier Windows versions and platforms that lack support for Kernel DMA Protection, please refer to Intel Thunderbolt™ 3 Security documentation.
SOLUTION
- If you are running both, Kernel DMA Protection isn't compatible with other BitLocker DMA attacks countermeasures.
- The Microsoft article recommends to disable the BitLocker DMA attacks countermeasures if the system supports Kernel DMA Protection. Kernel DMA Protection provides higher security bar for the system over the BitLocker DMA attack countermeasures, while maintaining usability of external peripherals.
- We have found that disabling KernelDMA works better than trying to decipher which BitLocker DMA attack countermeasures to disable.
- If you are running an older version of Windows 10 (build 1709) and your devices are not working before you log on to a computer then you can follow the resolution steps described by the MS team here.
