drm/atomic: Don't potentially reset color_mgmt_changed on successive property updates.

Due to assigning the 'replaced' value instead of or'ing it,
if drm_atomic_crtc_set_property() gets called multiple times,
the last call will define the color_mgmt_changed flag, so
a non-updating call to a property can reset the flag and
prevent actual hw state updates required by preceding
property updates.
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: <stable@vger.kernel.org> # v4.6+
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_atomic.c

@@ -475,7 +475,7 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
 					val,
 					-1,
 					&replaced);
-		state->color_mgmt_changed = replaced;
+		state->color_mgmt_changed |= replaced;
 		return ret;
 	} else if (property == config->ctm_property) {
 		ret = drm_atomic_replace_property_blob_from_id(crtc,
@@ -483,7 +483,7 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
 					val,
 					sizeof(struct drm_color_ctm),
 					&replaced);
-		state->color_mgmt_changed = replaced;
+		state->color_mgmt_changed |= replaced;
 		return ret;
 	} else if (property == config->gamma_lut_property) {
 		ret = drm_atomic_replace_property_blob_from_id(crtc,
@@ -491,7 +491,7 @@ int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
 					val,
 					-1,
 					&replaced);
-		state->color_mgmt_changed = replaced;
+		state->color_mgmt_changed |= replaced;
 		return ret;
 	} else if (crtc->funcs->atomic_set_property)
 		return crtc->funcs->atomic_set_property(crtc, state, property, val);