linux – Set xrandr DPI failure

I’m not exactly sure where to search for this, other than Google, which I have tried.

Normally, I use xrandr to set my DPI level after my Window Manager or DE has started. After making some xrandr layout changes, I get an error with running xrandr --dpi 120.

$ xrandr --dpi 120
X Error of failed request:  BadMatch (invalid parameter attributes)
  Major opcode of failed request:  140 (RANDR)
  Minor opcode of failed request:  7 (RRSetScreenSize)
  Serial number of failed request:  46
  Current serial number in output stream:  48

This issue began happening after I swapped my xrandr setup for HDMI-0 from --auto to --auto --scale 0.7x0.7.

My relevant i3 config:

exec --no-startup-id xrandr --output DP-2 --mode 2560x1440 --refresh 74.99 --primary --output HDMI-0 --auto --scale 0.7x0.7 --left-of DP-2
exec --no-startup-id xrandr --dpi 120

Previously, it was:

exec --no-startup-id xrandr --output DP-2 --mode 2560x1440 --refresh 74.99 --primary --output HDMI-0 --auto --left-of DP-2
exec --no-startup-id xrandr --dpi 120

I’m not exactly sure how to pinpoint the brokenness here, so out of desperation I’m inquiring superusers to see if they know of any relevant details regarding this problem.