colors are wrong on one screen with Radeon RX Vega M GL and Kernel 4.18

Submitted by Mauro Chehab @mchehab

Assigned to Default DRI bug account

Link to original bug (#107889)

Description

Created attachment 141508
Picture with the 3 monitors. The colors at the center one are wrong

I have a 3 monitors setup on a NUC8i7HNK (with latest BIOS: 0049).

I'm currently using Kernel 4.17 + DRM patches for 4.18-rc1. Everything works OK. However, upgrading the Kernel to 4.18.5 (kernel-4.18.5-200.fc28.x86_64) causes that the center (and default) monitor to mangle colors. The same issue also happens with upstream Kernel 4.18 vanilla.

I'm enclosing a picture of what's happening there.

Attachment 141508, "Picture with the 3 monitors. The colors at the center one are wrong":