wrong colors & cursor gamma vs. modesetting/Wayland on RDNA2
Since I've swapped my RX 5700 XT with an RX 6800, some colors are very noticeably off with xf86-video-amdgpu. It is very noticeable with the top blue bar on GitHub where the last commit and the total number of commits are listed (Example site: https://github.com/torvalds/linux ) . With xf86-video-amdgpu, the top bar's blue color is rather turquoise instead of the regular colder blue tone. This can't be captured in screenshots. When opening such a screenshot with xf86-video-amdgpu, it's still turquoise, whereas with modesetting DDX (or Wayland) it's the regular blue tone. For testing reasons, I forcefully deleted colord so no color adjustments could take place, but the issue was unchanged. It happens also in every browser and also with color calibration turned off (e.g. gfx.color_management.mode = 0 in Firefox).
Perhaps another aspect of the same issue: There seems to be a too dark gamma applied to the hardware cursor. This is not visible with many typical desktop cursor themes which are either black or white, but e.g. when games change the cursor theme this gets apparent. This also only occurs with xf86-video-amdgpu and only since the RDNA2 card is installed.
Tested with Linux 5.11 and 5.12-rc1* (*should not be used with swap). I've also tested without any kernel command line argument like custom EDID. Arch Linux, Xorg 1.20.10, xf86-video-amdgpu 19.1 & git-master.