From dbe950b44890665992b58fc92f19011434bf68bf Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.com>
Date: Mon, 21 Feb 2022 10:59:03 +0100
Subject: drm/object: Add default zpos value at reset
Git-commit: 1a7998dab5dd3d11bada7e3921781922082e7fe6
Patch-mainline: v5.18-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

The drm_plane_create_zpos_property() function asks for an initial value,
and will set the associated plane state variable with that value if a
state is present.

However, that function is usually called at a time where there's no
state yet. Since the drm_plane_state reset helper doesn't take care of
reading that value when it's called, it means that in most cases the
initial value will be 0, or the drivers will have to work around it.

Let's add some code in __drm_atomic_helper_plane_state_reset() to get
the initial zpos value if the property has been attached in order to fix
this.

Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220221095918.18763-8-maxime@cerno.tech
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/drm_atomic_state_helper.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c
index ddcf5c2c8e6a..1412cee404ca 100644
--- a/drivers/gpu/drm/drm_atomic_state_helper.c
+++ b/drivers/gpu/drm/drm_atomic_state_helper.c
@@ -243,11 +243,22 @@ EXPORT_SYMBOL(drm_atomic_helper_crtc_destroy_state);
 void __drm_atomic_helper_plane_state_reset(struct drm_plane_state *plane_state,
 					   struct drm_plane *plane)
 {
+	u64 val;
+
 	plane_state->plane = plane;
 	plane_state->rotation = DRM_MODE_ROTATE_0;
 
 	plane_state->alpha = DRM_BLEND_ALPHA_OPAQUE;
 	plane_state->pixel_blend_mode = DRM_MODE_BLEND_PREMULTI;
+
+	if (plane->zpos_property) {
+		if (!drm_object_property_get_default_value(&plane->base,
+							   plane->zpos_property,
+							   &val)) {
+			plane_state->zpos = val;
+			plane_state->normalized_zpos = val;
+		}
+	}
 }
 EXPORT_SYMBOL(__drm_atomic_helper_plane_state_reset);
 
-- 
2.38.1