Colors are always washed out on reboot. I have to set RGB range to full on every login.
STEPS TO REPRODUCE
1. Install and use GDM instead of SDDM. GDM already runs on full range color. I have added
`ExecStartPre=/usr/bin/proptest -M i915 -D /dev/dri/card0 103 connector 98 1`
on gdm system service.
2. Login to plasma session.
The preference full range should stick on every reboot. It goes to automatic range which is not correct resulting in washed out colors.
KDE Plasma Version: 5.23.4
update: It happens when using on SDDM too. it's not specific to gdm.
Thankfully this should be fixed in Plasma 5.24 where there is official support for this in KScreen.
Support has been added in 5.23, this is a dup of 442520 (/of the latest issue reported in that bug report). I'll try to reproduce it again...
*** This bug has been marked as a duplicate of bug 442520 ***
The bug https://bugs.kde.org/show_bug.cgi?id=442520 description mentions it fails apply full rgb range. For me it applies rgb range but it doesn't work on re-login.
Read the newer comments, it's the same issue. Applying works, but it resets on logout/login somehow.