The first patch got rejected with the most recent 4.15 kernel source pulled
using the PKGBUILD file (Feb 14, 2018). The reject file contains:

--- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -2523,6 +2545,8 @@ static const struct drm_crtc_funcs amdgpu_dm_crtc_funcs =
{
        .atomic_duplicate_state = dm_crtc_duplicate_state,
        .atomic_destroy_state = dm_crtc_destroy_state,
        .set_crc_source = amdgpu_dm_crtc_set_crc_source,
+       .enable_vblank = dm_enable_vblank,
+       .disable_vblank = dm_disable_vblank,
 };

 static enum drm_connector_status

In the original amdgpu_dm.c:

/* Implemented only the options currently availible for the driver */
static const struct drm_crtc_funcs amdgpu_dm_crtc_funcs = {
        .reset = dm_crtc_reset_state,
        .destroy = amdgpu_dm_crtc_destroy,
        .gamma_set = drm_atomic_helper_legacy_gamma_set,
        .set_config = drm_atomic_helper_set_config,
        .page_flip = drm_atomic_helper_page_flip,
        .atomic_duplicate_state = dm_crtc_duplicate_state,
        .atomic_destroy_state = dm_crtc_destroy_state,
};

This line:

.set_crc_source = amdgpu_dm_crtc_set_crc_source,

is not there.