Can't change the DPI in Xorg

General system Kernel, boot, graphics & hardware
1

I have openbox with Xorg and lightdm, and everything is really small on my 3072x1920 screen, so I wanted to change the DPI. I added this line to the lightdm.conf file (rest is commented):

xserver-command=X -dpi 210

But the screen stays the same. When I run grep DPI /var/log/Xorg.0.log I get this output:

[     6.721] (==) AMDGPU(0): DPI set to (96, 96)
[     8.379] (WW) NVIDIA(G0): Unable to get display device for DPI computation.
[     8.379] (==) NVIDIA(G0): DPI set to (75, 75); computed from built-in default
[     8.681] (==) modeset(G1): DPI set to (96, 96)
[     9.604] (==) modeset(G1): DPI set to (96, 96)

Am I doing something wrong or is this a bug?

2

Welcome,

You also can try to change the display size.

https://wiki.archlinux.org/title/xorg#Display_size_and_DPI

3

That kind of worked, but now the title bars and everything openbox related is very big and all the apps stayed the same.

dpi
dpi3071×1919 273 KB

4

What about xrand before launching openbox-session

xrandr --output xxxxxxx --dpi 210
5

Bit of a dumb issue, but I’m not exactly sure what to put in output. “Screen 0” doesn’t work, nor do any other items on the list.

Here’s the result of xrandr --current

Screen 0: minimum 320 x 200, current 3072 x 1920, maximum 16384 x 16384
eDP connected primary 3072x1920+0+0 (normal left inverted right x axis y axis) 312mm x 195mm
   3072x1920     60.00*+ 120.00  
   1920x1200     60.00  
   1920x1080     60.00  
   1600x1200     60.00  
   1680x1050     60.00  
   1280x1024     60.00  
   1440x900      60.00  
   1280x800      60.00  
   1280x720      60.00  
   1024x768      60.00  
   800x600       60.00  
   640x480       60.00  
HDMI-A-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 disconnected (normal left inverted right x axis y axis)
DisplayPort-2 disconnected (normal left inverted right x axis y axis)
DisplayPort-3 disconnected (normal left inverted right x axis y axis)
DisplayPort-4 disconnected (normal left inverted right x axis y axis)
DisplayPort-5 disconnected (normal left inverted right x axis y axis)
6

The one that is connected, so eDP for you.

7

Ok yeah that didn’t work either. I’m starting to think there might be a deeper issue here.

8

The link you were given has several options to try. What exactly had you modified, and how did you test it?

This is included in the above link/article:

xrandr --dpi 144

FWIW, I would change gtk font size (with lxappearance or similar utility).

9

The link you were given has several options to try. What exactly had you modified, and how did you test it?

image
image979×167 22.3 KB

Made a file with exactly that name and those contents, then rebooted. Later changed the display name, still same result.
And xrandr --dpi doesn’t work either way.

Edit: Now that I think about it, obenbox does scale properly when I do that, the DPI is set correctly now, the apps just don’t really want to comply…

10

Try the standard methods.