X server found. dri2 connection failed! [Fedora 27 i3wm]

[dylhack]

(edit: sorry for the no-explanation, I quickly posted this before an event)
When trying to run ethminer on Fedora it kept failing even when configuring the files.
X server found. dri2 connection failed!
DRM_IOCTL_I915_GEM_APERTURE failed: Invalid argument
Assuming 131072kB available aperture size.
May lead to reduced performance or incorrect rendering.
get chip id failed: -1 [22]
param: 4, val: 0
No GPU device with sufficient memory was found. Can't GPU mine. Remove the -G argument

screenfetch:
Fedora 27, i3wm
Kernel: x86_64 Linux 4.14.13-300.fc27.x86_64
GPU: GeForce GTX 970/PCIe/SSE2
CPU: Intel Core i5-4690K @ 4x 3.9GH

[AndreaLanfranchi]

When running on NVIDIA use CUDA instead of OpenCL.

ethminer -U [...]

instead of

ethminer -G [...]

[DeadManWalkingTO]

I think this issue can be closed.

[piotr-dobrogost]

When running on NVIDIA use CUDA instead of OpenCL.

Theoretically it should be perfectly possible to mine on NVidia via OpenCL (not recommended of course but still), no?
I found this thread as I got the exact same error (X server found. dri2 connection failed!) while trying to run John The Ripper on NVidia cards via OpenCL (JtR removed support for CUDA some time ago and only supports OpenCL).

Anyone knows possible reason for error X server found. dri2 connection failed! when using OpenCL with NVidia cards?