[SOLVED] Best practice handling 4k monitor and multihead

jLuca · 2019-02-06 15:47:36

Hello guys, I installed Arch on my laptop which has a high-resolution monitor (4k):

[lucs@partenopeo ~]$ xdpyinfo | grep -B 2 resolution
screen #0:
  dimensions:    5760x2160 pixels (1524x571 millimeters)
  resolution:    96x96 dots per inch

Normally I disable this display with kernel parameters\xrandr and I use only an external display which has a lower resolution and its size is bigger:

[lucs@partenopeo scripts]$ xdpyinfo | grep -B 2 resolution
screen #0:
  dimensions:    1920x1080 pixels (507x285 millimeters)
  resolution:    96x96 dots per inch

There are times when I have to use my laptop around and I find myself with the 4k display and my user experience it's a mess:

Grub entries are too small
Console and terminal emulator output (text) it's too small
Icons and other graphics elements are too small
Etc...

I would like your help to:
1) Best practice to handle the 4k monitor
2) Best practice to detect and handle (automatically possibly) the switching from the external display and the 4k one
3) Best practice to handle multi-head use with huge resolution difference between screens

In particular, I tried to read the wiki around but I'm not sure what concepts should I focus on and why, I read about framebuffer, dpi, font sizes, etc.

Thanks! Luca

Last edited by jLuca (2019-04-08 19:08:17)

seth · 2019-02-06 16:29:58

It seems either you or your DE or some daemon configures a resolution of 96DPI, what gets you int trouble. Just stop that.
This should also resolve multihead (zaphod) setups BUT: if you actually just mean a setup w/ multiple outputs (where you can move windows from one monitor to another) there's no great approach. Basically you can either scale the FullHD output up to match the resolution of the 4k one or drive the latter at a lower resolution. The former will be more resource intense but you get a better picture on the 4K output.

jLuca · 2019-02-06 17:10:14

I will try to play around with the concept of DPI then if I got your answer correctly. I didn't configure anything that I'm aware of, maybe that's the problem (X server + i3 wm).

What about the grub\console user experience?

Regarding multihead use, I meant sending the video output to two display at the same time, either in "extend mode" or "duplicate mode" (e.g. Windows). So basically, as you said, I actually mean a setup w/ multiple outputs (where you can move windows from one monitor to another for instance). I will try to deal with the 4k monitor alone, for now. What really pisses me off is the text too small on the 4k monitor so maybe fixing the DPI is the answer I was searching for.

seth · 2019-02-06 17:17:29

You'll only ever get one DPI per X11 server (ie. you cannot have different DPI per output what means any value will either be too big or too small unless you scale one of the outputs)
I don't think i3wm itself will set the resolution. Something might call "xrandr --dpi 96" or, if you've an nvidia GPU, it might be in the xorg config.

As for the console:
https://wiki.archlinux.org/index.php/GR … resolution
https://wiki.archlinux.org/index.php/GR … ramebuffer

jLuca · 2019-04-08 19:09:01

Thanks, marked as solved. I ended up changing the DPI on fly when needed.

Arch Linux

#1 2019-02-06 15:47:36

[SOLVED] Best practice handling 4k monitor and multihead

#2 2019-02-06 16:29:58

Re: [SOLVED] Best practice handling 4k monitor and multihead

#3 2019-02-06 17:10:14

Re: [SOLVED] Best practice handling 4k monitor and multihead

#4 2019-02-06 17:17:29

Re: [SOLVED] Best practice handling 4k monitor and multihead

#5 2019-04-08 19:09:01

Re: [SOLVED] Best practice handling 4k monitor and multihead

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