I found out that 'nouveau' driver comes with linux-image-extra package and prevents 'nvidia' driver from being loaded. I blacklisted nouveau:
$ sudo -i
# echo "blacklist nouveau" > /etc/modprobe.d/blacklist-nouveau.conf
# update-initramfs -u -k all
# reboot
Finally everything works for me!
I found out that 'nouveau' driver comes with linux-image-extra package and prevents 'nvidia' driver from being loaded. I blacklisted nouveau: d/blacklist- nouveau. conf
$ sudo -i
# echo "blacklist nouveau" > /etc/modprobe.
# update-initramfs -u -k all
# reboot
Finally everything works for me!