Comment 22 for bug 1637733

I experienced a similar situation with a fresh installation of Ubuntu Gnome on Dell XPS 15. I didn't install virtual box.

Details about my computer:

Processor: Intel® Core™ i7-7700HQ CPU @ 2.80GHz
Graphics: GeForce GTX 1050/PCIe/SSE2
Driver: Nvidia binary driver version 384.90; Processor microcode from intel-microcode(proprietary)

After running "prime-select intel" and log out, I couldn't log in again. When I tried to log in, the screen just blanked out and got back to log in screen after a few seconds. After I run "prime-select nvidia" in tty to restore settings, I can log in.

The solution on #11 didn't work for me. It successfully shut down the graphics, but I couldn't open GUI anymore and had to reboot to power up the graphics.

However, I did find some workaround if you just want to reduce the power consumption. Instead of shutting down the graphics, you may constrain the clock rate by using this method:

https://devtalk.nvidia.com/default/topic/572053/linux/-solved-forcing-maximum-power-saving-on-the-desktop-quot-minimum-power-quot-mode-for-powermizer-/

It worked on my computer and helped me to get rid of the annoying sound from GPU fan.