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tigerjack

Member

Registered: 2017-08-20

Posts: 99

GPU screen and tty

I have a setup in which two monitors are connected to the Intel GPU, and one the Nvidia GPU.

$>lspci -k -d ::03xx
00:02.0 Display controller: Intel Corporation 4th Generation Core Processor Family Integrated Graphics Controller (rev 06)
	Subsystem: ASRock Incorporation Device 041e
	Kernel driver in use: i915
	Kernel modules: i915
01:00.0 VGA compatible controller: NVIDIA Corporation GP107 [GeForce GTX 1050] (rev a1)
	Subsystem: ZOTAC International (MCO) Ltd. Device 2454
	Kernel driver in use: nouveau
	Kernel modules: nouveau

There are two issues that I'd like to solve:
1. The login screen (like the GRUB prompt and everything before sway launch) is directed on the GPU screen. This wouldn't be so annoying if such a monitor wouldn't be vertical.
2. When I switch between tty's, only the GPU monitor shows the tty, while the other ones keep showing the windows open.

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,142

Re: GPU screen and tty

If it's at all possible you should ideally just pick one GPU as this setups has a few gotchas that might eventually bite you, but none are relevant to the questions so just consider that an aside.

1. All of that is first and foremost relevant to your UEFI/BIOS configuration and it's monitor/card initalisation order and can generally not be influenced at that stage GRUB is loading at, check whether you can configure which GPU should be considered primary there. For the stuff after GRUB you might be able to setup some video= configs: https://www.kernel.org/doc/Documentation/fb/modedb.txt

2. That one I don't actually have a direct answer for, but it's probably a PITA to try and set up as the TTY framebuffer is generally allocated to a single card... That said - whenever something like this comes up, my main question is what's the point of wanting to do this? Unless you're debugging an actual GPU freeze issue, all you get is an inferior terminal that lacks a scrollback buffer and will often not be at the best resolution. If you want a fullscreen terminal, just pick any terminal emulator you like and make that fullscreen on the xorg session screen you want a terminal on, issue solved, without the awkward modeset transition blockers and without loss of functionality. I get the "cause I can" effect, but there's so little to not tangible benefit to it.

Last edited by V1del (2025-02-11 16:28:49)

tigerjack

Member

Registered: 2017-08-20

Posts: 99

Re: GPU screen and tty

If it's at all possible you should ideally just pick one GPU as this setups has a few gotchas that might eventually bite you, but none are relevant to the questions so just consider that an aside.

I get you, but to have multiple monitors having the other GPU is the only viable option unfortunately.

All of that is first and foremost relevant to your UEFI/BIOS configuration and it's monitor/card initalisation order and can generally not be influenced at that stage GRUB is loading at, check whether you can configure which GPU should be considered primary there.

I already tried that path unfortunately, but apparently the problem is with the motherboard https://forum.asrock.com/forum_posts.asp?TID=23433.
Meaning, even if I select "Onboard" as primary monitor, if "iGPU multi monitor" is enabled the output still goes to the external GPU.
That's why I wanted to affect only from Grub on.

For the stuff after GRUB you might be able to setup some video= configs: https://www.kernel.org/doc/Documentation/fb/modedb.txt

So, I was thinking of adding the last three options to GRUB

GRUB_CMDLINE_LINUX_DEFAULT="loglevel=3 quiet splash nouveau.config=NvGspRm=1 i915.modeset=1 nouveau.modeset=1 video=VGA-1:d video=HDMI-A-3:d video=HDMI-A-1:e"

Do you think it's the right way?

That one I don't actually have a direct answer for, but it's probably a PITA to try and set up as the TTY framebuffer is generally allocated to a single card... That said - whenever something like this comes up, my main question is what's the point of wanting to do this? Unless you're debugging an actual GPU freeze issue, all you get is an inferior terminal that lacks a scrollback buffer and will often not be at the best resolution. If you want a fullscreen terminal, just pick any terminal emulator you like and make that fullscreen on the xorg session screen you want a terminal on, issue solved, without the awkward modeset transition blockers and without loss of functionality. I get the "cause I can" effect, but there's so little to not tangible benefit to it.

I understand your point, and yeah, probably it's not worth the pain. My main concerns where usually privacy-related, since sometimes I have to open a TTY and all my mails are opened on the other displays.
Let me change the question then. Can I have the tty framebuffer ONLY on the integrated GPU?

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 75,086

Re: GPU screen and tty

https://raw.githubusercontent.com/torva … /fbcon.rst - specifically the "fbcon=map:123" paragraph will allow you to control what VT shows up on which GPU

On top of that, "i915.modeset=1 nouveau.modeset=1" is default anyway, but "nvidia_drm.modeset=1" will block the simpledrm device and in return restore the natural order of cards what should™ make the IGP the primary one, unless you maybe have nouveau in the initramfs, but not i915? Try adding the latter there.

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