How to show tty login screen on external monitor when using switchable graphics

Graphics / Linux Linux
1

Hi, I have a Lenovo Legion Y540-15IRH 81SX 81SX0008MX laptop which I have installed Linux Arch on. The laptop uses the Optimus technology and has a NVIDIA GeForce GTX 1660 Ti Mobile discrete GPU as well as an Intel CoffeeLake-H GT2 [UHD Graphics 630] integrated GPU.

I would like to make the tty login screen show on my external monitor when I boot up my laptop. I can achieve that by setting my laptop to use discrete graphics in the BIOS and using the kernel parameter nvidia-drm.modeset=1. If I do not set the kernel parameter (but still use discrete graphics) then I do not see the tty login screen on my external monitor at boot up, but it appears on the external monitor if I switch to another virtual console using Alt+F2 after having entered an Xorg display server.

However, I would like to use switchable graphics so I can save battery when the discrete GPU is not needed. I this case I have not been successful in making the tty login screen appear at all on the external monitor. Neither at boot up or after entering an Xorg display server. The Xorg display server itself does appear on the external monitor. Do you have an idea how this can be solved?

This is the output of cat /proc/fb when using switchable graphics:
0 i915drmfb

This is the output of cat /proc/fb when using discrete graphics:
0 EFI VGA

I have made a post here some time ago trying to solve it without success unfortunately: Is it possible to show tty login screen on external monitor? / Newbie Corner / Arch Linux Forums

2

I don’t think that’s possible, the kernel displays the console on the device it gets handed over from the uefi firmware.

3

So to make it work the uefi would have to be changed such that the external monitor is handed over if plugged in?

4

Yes.