tty console on external monitor

ss · 2018-12-25 17:00:53

My laptop is connected to an external monitor via a VGA connector. The laptop screen has a resolution of 1280x800, while the external monitor is 1920x1080. Everything works fine under X, I can use xrandr to extend or mirror the laptop screen to the external one, with both having the proper resolution.

However, under Linux console it seems that the VGA output can only mirror the laptop screen with a fixed resolution of 1024x768. The content on the external monitor is incomplete. I have no idea how to specify the output resolution of the VGA port because obviously xrandr won't work in this case.

Any suggestions?

Is it in principle possible to run multihead setup in tty console without X server? The Arch wiki article about multihead doesn't address this topic. And what about framebuffer? By default there is only one framebuffer device /dev/fb0, although I have two physical monitors. Is it possible to create another fb device for the external monitor?

Trilby · 2018-12-25 17:20:13

ss wrote:

Is it in principle possible to run multihead setup in tty console without X server?

I'm pretty sure it's not. Certainly with an elaborate enough framebuffer set up, you could - but this is not then the linux console but essentially becomes a reinvented X or wayland.

You can set a different resolution for the console (as a kernel parameter) and assuming there was a resolution that both physical screens shared, then it would "mirror" properly, but this would almost certainly not be the ideal resolution for either monitor.

Last edited by Trilby (2018-12-25 17:21:57)

ss · 2018-12-26 10:59:12

I am just wondering what if I don't need a 'complete solution', does it have to be so sophisticated as an X or Wayland replacement? Let's say I don't need monitor extension nor moving windows and workspaces between the monitors. Isn't it possible to show tty console on one screen and map the framebuffer to another? I would be totally happy with that.

I thought at least it would be possible to adjust the 'default' resolution of the VGA output. Now it is fixed at 1024x768, which is different from the laptop screen (1280x800). But as shown under X, that VGA port is capable of full hd output. I even did a test where I first start a dual monitor setup under X, then switch to another tty. In my external monitor I can check what kind of signal it is actually receiving. And I can confirm that it is changed from full hd to 1024x768 as soon as I switched to tty from X.

But I don't even know what terms or keywords to look for so that I can learn more about this topic. Any further hints are appreciated. Thank you!

unixman · 2018-12-26 12:03:50

I am not sure it can helps or related.

quote from below link wrote:

What are the features of fbcon? The framebuffer console supports high resolutions, varying font types, display rotation, primitive multihead ....

https://www.mjmwired.net/kernel/Documen … /fbcon.txt

Last edited by unixman (2018-12-26 12:05:05)

Arch Linux

#1 2018-12-25 17:00:53

tty console on external monitor

#2 2018-12-25 17:20:13

Re: tty console on external monitor

#3 2018-12-26 10:59:12

Re: tty console on external monitor

#4 2018-12-26 12:03:50

Re: tty console on external monitor

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