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

[Brian Starkey]

Hi Alex,

On Thu, Aug 23, 2018 at 04:11:17PM +0100, Alexandru Gheorghe wrote:
>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>

LGTM.

Reviewed-by: Brian Starkey <brian.starkey 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
>