1. /# ls -l /dev/{fb0,dri/}
  2. crw-rw---- 1 root video 29, 0 Dec 22 15:56 /dev/fb0
  3. /dev/dri/:
  4. total 0
  5. crw-rw----+ 1 root video 226, 0 Dec 22 15:56 card0
  6. crw-rw----+ 1 root video 226, 1 Dec 22 15:56 card1
  7. crw-rw---- 1 root video 226, 64 Dec 22 15:56 controlD64
  8. crw-rw----+ 1 root video 226, 128 Dec 22 15:56 renderD128
  9. crw-rw----+ 1 root video 226, 129 Dec 22 15:56 renderD129

This are my devices:

2 cards:

i915( display )

GTX 1060 6GB( card only for CUDA )