drm/doc: Interlink color manager docs better

Motivated by a request from Eric.

v2: Take in suggestions from Lionel

Cc: Eric Anholt <eric@anholt.net>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170412152006.12233-1-daniel.vetter@ffwll.ch
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 8be9719..cfeda5f 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -3517,7 +3517,8 @@ EXPORT_SYMBOL(drm_atomic_helper_connector_destroy_state);
  *
  * Implements support for legacy gamma correction table for drivers
  * that support color management through the DEGAMMA_LUT/GAMMA_LUT
- * properties.
+ * properties. See drm_crtc_enable_color_mgmt() and the containing chapter for
+ * how the atomic color management and gamma tables work.
  */
 int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
 				       u16 *red, u16 *green, u16 *blue,