[PATCH v4 6/6] drm/omap: Use normalized zpos for plane placement

[Peter Ujfalusi]

Planes with identical zpos value will result undefined behavior:
disappearing planes, screen flickering and it is not supported by the
hardware.

Use normalized zpos to make sure that we don't encounter invalid
configuration.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi at ti.com>
CC: Tomi Valkeinen <tomi.valkeinen at ti.com>
Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/omapdrm/omap_drv.c   | 3 +++
 drivers/gpu/drm/omapdrm/omap_plane.c | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c
index dd68b2556f5b..37ee20c773c7 100644
--- a/drivers/gpu/drm/omapdrm/omap_drv.c
+++ b/drivers/gpu/drm/omapdrm/omap_drv.c
@@ -316,6 +316,9 @@ static int omap_modeset_init(struct drm_device *dev)
 	dev->mode_config.max_width = 2048;
 	dev->mode_config.max_height = 2048;
 
+	/* We want the zpos to be normalized */
+	dev->mode_config.normalize_zpos = true;
+
 	dev->mode_config.funcs = &omap_mode_config_funcs;
 	dev->mode_config.helper_private = &omap_mode_config_helper_funcs;
 
diff --git a/drivers/gpu/drm/omapdrm/omap_plane.c b/drivers/gpu/drm/omapdrm/omap_plane.c
index 7d789d1551a1..2c19d2239bc5 100644
--- a/drivers/gpu/drm/omapdrm/omap_plane.c
+++ b/drivers/gpu/drm/omapdrm/omap_plane.c
@@ -65,7 +65,7 @@ static void omap_plane_atomic_update(struct drm_plane *plane,
 	info.rotation_type = OMAP_DSS_ROT_NONE;
 	info.rotation = DRM_MODE_ROTATE_0;
 	info.global_alpha = 0xff;
-	info.zorder = state->zpos;
+	info.zorder = state->normalized_zpos;
 
 	/* update scanout: */
 	omap_framebuffer_update_scanout(state->fb, state, &info);
-- 
Peter

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