Created attachment 275079 [details]
dmesg messages

I'm running amdgpu on my Kaveri for quite some time and it works fine. Nothing changed with kernel 4.16 there.
For a test, I tried it with activated DC as well:
CONFIG_DRM_AMDGPU=y
# CONFIG_DRM_AMDGPU_SI is not set
CONFIG_DRM_AMDGPU_CIK=y
# CONFIG_DRM_AMDGPU_USERPTR is not set
# CONFIG_DRM_AMDGPU_GART_DEBUGFS is not set
CONFIG_DRM_AMD_ACP=y
CONFIG_DRM_AMD_DC=y
CONFIG_DRM_AMD_DC_PRE_VEGA=y

It did boot fine with this config and on the DVI output, the image looked normal.
However, on the HDMI output, there was a pink/purple tint as if green was missing in the output.
In the dmsg output, I can find these messages (full output attached):
Apr 02 15:36:44 orionis kernel: [drm:construct] *ERROR* construct: Invalid Connector ObjectID from Adapter Service for connector index:1! type 0 expected 3
Apr 02 15:36:44 orionis kernel: [drm:construct] *ERROR* construct: Invalid Connector ObjectID from Adapter Service for connector index:3! type 0 expected 3
Apr 02 15:36:44 orionis kernel: [drm:construct] *ERROR* construct: Invalid Connector ObjectID from Adapter Service for connector index:5! type 0 expected 3

There is also this, but I don't know if it could be related:
Apr 02 15:36:44 orionis kernel: ACPI BIOS Error (bug): Failure looking up [\_SB.ALIB], AE_NOT_FOUND (20180105/psargs-364)
Apr 02 15:36:44 orionis kernel: ACPI Error: Method parse/execution failed \_SB.PCI0.VGA.ATC0, AE_NOT_FOUND (20180105/psparse-550)
Apr 02 15:36:44 orionis kernel: ACPI Error: Method parse/execution failed \_SB.PCI0.VGA.ATCS, AE_NOT_FOUND (20180105/psparse-550)

Apart from that, there didn't seem to be any error messages that could be related to drm at a first glance.