HUGE scaling issue on Nvidia and KDE environment

Some explanations for future readers and possibly OP better application of the solution.

  • Screen resolution is correct (two monitors side by side)
  • Notice the actual recognized-as monitor dimensions!!
  • While Mon-2 looks fine (48cm x 27cm - 21"), Mon-1 looks like a large… smartphone :rofl: (16cm x 9 cm - 7"). I guess it’s not true(??):stuck_out_tongue_winking_eye: These are not rare issues with Xorg <==> EDID misunderstandings.
  • SDDM is probably set to use auto-HiDPI scaling.
  • Xorg thinks/serves Mon-1 as HiDPI and SDDM… believes him! :cry:

There are two possible approaches, that one or both could work, but sometimes are difficult to configure. Use the easiest successful one.

  • Fix/correct Xorg monitor-1 resolution/dpi/modeline, using an xorg conf file in /etc/X11/xorg.conf.d/monitor-dp-1.conf with a proper Section Monitor.
  • Fix SDDM configuration, changing HiDPI to disabled
[X11]
EnableHiDPI=false

and/or

  • adding a working dpi value at Xorg server flags (as was successfully advised by @FGD )

…but… using the proper/suggested drop-in file in

/etc/sddm.conf.d/hidpi.conf

and deleting /etc/sddm.conf, which is deprecated and used as fallback (overrides all drop-in settings).


Once again, always check Archwiki for proper guidance, instead of random (years old :wink: ) forum/web advice.
Keep up the good work @FGD :+1:

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