CUDA not working without X server

Tried to start CUDA programs on Ubuntu without x server. Disabled X with “sudo service lightdm stop”. Then started some CUDA programs and tried cuda-dbg. Every CUDA program caused weird glitches on screen and even stops execution with error on most runs. Attached photo with matrixMul example from CUDA samples.

Tried on Ubuntu 64-bit 13.04, 12.04 with CUDA Toolkit 5.5, 5 respectively
Nvidia driver 319.23

Tried to use script

if [ "$?" -eq 0 ]; then
# Count the number of NVIDIA controllers found.
N3D=`/sbin/lspci | grep -i NVIDIA | grep "3D controller" | wc -l`
NVGA=`/sbin/lspci | grep -i NVIDIA | grep "VGA compatible controller" | wc -l`

N=`expr $N3D + $NVGA - 1`
for i in `seq 0 $N`; do
mknod -m 660 /dev/nvidia$i c 195 $i

mknod -m 660 /dev/nvidiactl c 195 255
exit 1

CUDA programs work fine when X server running.

Problem solved. After some experimentation found that glitch was caused by vesafb kernel module. Apparently it is not working with Nvidia display driver. I just disabled it with “vga=normal” added in grub configuration file and now CUDA programs work well without X.