更新nvidia显卡驱动，只能单显示器工作
https://forums.developer.nvidia.com/t/black-screen-after-install-of-nvidia-driver-ubuntu/109312
Please follow this:
delete /etc/X11/xorg.conf
make sure nvidia-prime is installed (sudo apt install --reinstall nvidia-prime)
switch to nvidia (sudo prime-select nvidia)
remove stray blacklist files (sudo rm /lib/modprobe.d/blacklist-nvidia.conf /etc/modprobe.d/blacklist-nvidia.conf)
update the initrd (sudo update-initramfs -u)
reboot
