LOL...yeah, active DP adapters are expensive, but passive or active depends on what your driving and it's requirements, and the video card your using and if it has mini DP or standard DP, in my case my wife (graphics designer) needed one for a Wacom Cintiq drawing tablet that was DP only and of course required a active adapter because the video card had the mini-DP port. This explains the difference and usage.
http://www.startech.com/faq/DisplayPort_Converter_DP_Multi_Mode
Have you checked your UEFI / BIOS if IOMMU is ENABLED?
The line
Suggests that there either is no IOMMU group of that name or the device is not present or you made a mistake with the descriptor for example forgetting zeroes at the front or forgetting the Subsystem ID as well as part of the ID.
If you lspci -nkks 02:00.0
you get the missing four digits and the “Subsystem” ID.
Have you tried updating the BIOS / UEFI / Firmware of your mainboard?
You can go with old professional cards.
They have mini display ports and the adapter cables are rather cheap.