From d7b66de513179065408908a79cfbe3a11a15e6eb Mon Sep 17 00:00:00 2001
From: Daniel Vetter <daniel.vetter@ffwll.ch>
Date: Tue, 20 Jun 2017 11:42:28 +0200
Subject: [PATCH] drm: More links for gamma support helpers
Git-commit: d7b66de513179065408908a79cfbe3a11a15e6eb
Patch-mainline: v4.14-rc1
References: FATE#322643 bsc#1055900

It's not obvious that when using the new color manager stuff you still
need to wire up the legacy helper to get legacy LUT support. Improve
this with more links. drm_crtc_funcs->gamma_set already explains this
properly.

Cc: Peter Rosin <peda@axentia.se>
Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170620094228.4757-1-daniel.vetter@ffwll.ch
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/drm_color_mgmt.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/gpu/drm/drm_color_mgmt.c
+++ b/drivers/gpu/drm/drm_color_mgmt.c
@@ -128,6 +128,9 @@ EXPORT_SYMBOL(drm_color_lut_extract);
  * optional. The gamma and degamma properties are only attached if
  * their size is not 0 and ctm_property is only attached if has_ctm is
  * true.
+ *
+ * Drivers should use drm_atomic_helper_legacy_gamma_set() to implement the
+ * legacy &drm_crtc_funcs.gamma_set callback.
  */
 void drm_crtc_enable_color_mgmt(struct drm_crtc *crtc,
 				uint degamma_lut_size,