Can't invert screen colors by adjusting the gamma ramp

Submitted by Vlad Zahorodnii @zzag

Assigned to Default DRI bug account

Link to original bug (#110677)

Description

On X11, there are several ways KWin can invert screen colors: either by using an OpenGL-based effect, or by adjusting the gamma ramp. While the former approach works well on most hardware, we experience some issues with the latter approach on AMD hardware.

After adjusting the gamma ramp, the screen is filled with mostly white color.

Steps to reproduce:

• Open System Settings, go to Shortcuts, select KWin component under Global Shortcuts tab, assign custom shortcut to "Invert Screen Colors";
  
• Press the shortcut.
  

(or just use xcalib -i)

Observed results:
The screen is filled with mostly white color.

Expected results:
Inverted screen.

Hardware: Radeon RX 580
Mesa: 19.0.3
Linux: 5.0.13
xorg: 1.20.4