[PATCH] drm: Fix crtc color management when doing suspend/resume

[Alexandru Gheorghe]

When doing suspend/resume drivers usually use the
drm_atomic_helper_suspend/drm_atomic_helper_resume pair for saving the
state and then re-comitting it.

The problems is that drm_crtc_state has a bool field called
color_mgmt_changed, which mali-dp and other drivers uses it to detect
if coefficients need to be reprogrammed, but that never happens
because the save state has color_mgmt_changed set to 0.

Fix that by setting color_mgmt_changed to true if the crtc duplicated
state differs from the reset state.

Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe at arm.com>
---
 drivers/gpu/drm/drm_atomic_helper.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 6dd5036545ec..e88aa62bc822 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -3196,8 +3196,13 @@ int drm_atomic_helper_commit_duplicated_state(struct drm_atomic_state *state,
 	for_each_new_plane_in_state(state, plane, new_plane_state, i)
 		state->planes[i].old_state = plane->state;
 
-	for_each_new_crtc_in_state(state, crtc, new_crtc_state, i)
+	for_each_new_crtc_in_state(state, crtc, new_crtc_state, i) {
 		state->crtcs[i].old_state = crtc->state;
+		new_crtc_state->color_mgmt_changed =
+			new_crtc_state->degamma_lut != crtc->state->degamma_lut ||
+			new_crtc_state->ctm != crtc->state->ctm ||
+			new_crtc_state->gamma_lut != crtc->state->gamma_lut;
+	}
 
 	for_each_new_connector_in_state(state, connector, new_conn_state, i)
 		state->connectors[i].old_state = connector->state;
-- 
2.18.0