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Using Ubuntu 20.04 Focal, with a dual monitor configuration, is it possible for X (or Wayland) to be configured only to use one monitor, and the other one to be pure TTY (as in, not a terminal emulator, just default boot-style TTY, unknown/unused by any GUI).

The reason I'd like this is because I have a very high resolution 5k x 2k monitor as primary, and my secondary one is much lower DPI. I don't like the idea that X-scaling "uses more resources" because this suggests some on-the-fly interpolation scheme which, apart from introduced latency, will almost certainly not play nice with sub-pixel font rendering, and will probably screw up integer scaling on graphical programs. Wayland by contrast just doesn't work with this configuration - multiple problems and basically crashes. So essentially I'd like to code in a terminal on the low-res TTY monitor, and have the main high DPI monitor run X (or wayland) with 100% scaling, no screwing around, though I'd probably raise the DPI setting.

Is this possible on one video card (Radeon VII). If not, would it be possible if running a secondary video card at the same time?

If it is possible, how would I switch focus of the keyboard between TTY monitor and GUI(Gnome) monitor? Run some kind of bash script to toggle focus maybe?

Thomas Browne
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  • Would it be feasible to run a separate box via terminal like raspberryPi through a remote connection (network like ssh) or KVM or something like that? A physically separate machine could accomplish this with a bit of latency but executed faithful to your wants. – Kris Driver Feb 21 '21 at 16:07

2 Answers2

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This is certainly not a definitive answer, as in most cases of an answer for the negative.

I think what you mean to accomplish is likely not possible, as all of the solutions for booting into text mode do so at the grub level. I hardly see a way that grub tells the OS to perform your intended actions.

Sources:

  1. How to boot to text only mode? Problem with laptop with Nvidia GPU
  2. https://dannyda.com/2019/06/19/turn-off-display-automatically-on-ubuntu-18-04-server-with-text-boot/
  3. https://unix.stackexchange.com/questions/17027/how-to-set-the-resolution-in-text-consoles-troubleshoot-when-any-vga-fail (very old)
  4. https://www.linuxuprising.com/2020/01/how-to-boot-to-console-text-mode-in.html

(Possibly) Related, and perhaps helping in finding a workaround, YMMV:

  1. Dual Monitor Setup : Grub loader goes to HDTV even if it is turned off
  2. Forcing grub menu to external monitor connected to laptop via HDMI/VGA
  3. https://help.ubuntu.com/community/MultiseatOneCard
  4. https://unix.stackexchange.com/questions/13619/how-do-i-prevent-xorg-using-my-linux-laptops-display-panel
  5. https://wiki.archlinux.org/index.php/Multihead
  6. https://wiki.archlinux.org/index.php/Extreme_Multihead
  • I think so too. TTY is useful because it bypasses non-essentials (gui) to operate if needed in an 'emergency'. Having X/Wayland running while in TTY would sort of defeat the utility of TTY fundamentally. GUI terminals are the equivalent to what the OP is trying to do. – Kris Driver Feb 21 '21 at 16:02
  • Bounty awarded to you for the great links, but I still wish that we had found a definitive answer. – Thomas Browne Feb 27 '21 at 12:03
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I tried for something a few years ago similar to this (my setup was for a set of televisions as opposed to a super high-def monitor) and I do not think this is possible at this point :( It's a good idea, and should exist, but I can't think of a real way to do this besides effectively having a dual-setup where one system hosts the tty and the other mounts that system 'remotely' for gui use. I wish I had solved it back then.

  • yes, I believe that you'd need to have 2 systems, of sorts. You could set up the "TTY" on the Serial port, and then put the serial port on the second screen, using a raspberry pi, or equivalent. You can't easily use 1 system because how would you select the screen of the TTY if it wasn't graphical? – Jad Feb 26 '21 at 10:02