Re: [PATCH] drm/tegra: Add blend mode properties

[Jon Hunter]

On 26/08/2026 11:54, Thierry Reding wrote:

From: Thierry Reding <tred...@nvidia.com>

The default programming in the driver matches the "coverage" blend mode,
so add the corresponding pixel blend mode property to let userspace know
about it.

Signed-off-by: Thierry Reding <tred...@nvidia.com>
---
  drivers/gpu/drm/tegra/dc.c  | 6 ++++++
  drivers/gpu/drm/tegra/hub.c | 2 ++
  2 files changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index 0b3fcc7011b35..fefc3761a4bc7 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -904,6 +904,7 @@ static struct drm_plane *tegra_primary_plane_create(struct 
drm_device *drm,
                                                    struct tegra_dc *dc)
  {
        unsigned long possible_crtcs = tegra_plane_get_possible_crtcs(drm);
+       unsigned int blend_caps = BIT(DRM_MODE_BLEND_COVERAGE);
        enum drm_plane_type type = DRM_PLANE_TYPE_PRIMARY;
        struct tegra_plane *plane;
        unsigned int num_formats;
@@ -939,6 +940,7 @@ static struct drm_plane *tegra_primary_plane_create(struct 
drm_device *drm,
        }

drm_plane_helper_add(&plane->base, &tegra_plane_helper_funcs);

+       drm_plane_create_blend_mode_property(&plane->base, blend_caps);
        drm_plane_create_zpos_property(&plane->base, plane->index, 0, 255);

err = drm_plane_create_rotation_property(&plane->base,

@@ -1209,6 +1211,7 @@ static struct drm_plane 
*tegra_dc_cursor_plane_create(struct drm_device *drm,
                                                      struct tegra_dc *dc)
  {
        unsigned long possible_crtcs = tegra_plane_get_possible_crtcs(drm);
+       unsigned int blend_caps = BIT(DRM_MODE_BLEND_COVERAGE);
        struct tegra_plane *plane;
        unsigned int num_formats;
        const u32 *formats;
@@ -1252,6 +1255,7 @@ static struct drm_plane 
*tegra_dc_cursor_plane_create(struct drm_device *drm,
        }

drm_plane_helper_add(&plane->base, &tegra_cursor_plane_helper_funcs);

+       drm_plane_create_blend_mode_property(&plane->base, blend_caps);
        drm_plane_create_zpos_immutable_property(&plane->base, 255);

return &plane->base;

@@ -1356,6 +1360,7 @@ static struct drm_plane 
*tegra_dc_overlay_plane_create(struct drm_device *drm,
                                                       bool cursor)
  {
        unsigned long possible_crtcs = tegra_plane_get_possible_crtcs(drm);
+       unsigned int blend_caps = BIT(DRM_MODE_BLEND_COVERAGE);
        struct tegra_plane *plane;
        unsigned int num_formats;
        enum drm_plane_type type;
@@ -1394,6 +1399,7 @@ static struct drm_plane 
*tegra_dc_overlay_plane_create(struct drm_device *drm,
        }

drm_plane_helper_add(&plane->base, &tegra_plane_helper_funcs);

+       drm_plane_create_blend_mode_property(&plane->base, blend_caps);
        drm_plane_create_zpos_property(&plane->base, plane->index, 0, 255);

err = drm_plane_create_rotation_property(&plane->base,

diff --git a/drivers/gpu/drm/tegra/hub.c b/drivers/gpu/drm/tegra/hub.c
index bd442bfd45407..448f49f3a7d7e 100644
--- a/drivers/gpu/drm/tegra/hub.c
+++ b/drivers/gpu/drm/tegra/hub.c
@@ -759,6 +759,7 @@ struct drm_plane *tegra_shared_plane_create(struct 
drm_device *drm,
                                            unsigned int index,
                                            enum drm_plane_type type)
  {
+       unsigned int blend_caps = BIT(DRM_MODE_BLEND_COVERAGE);
        struct tegra_drm *tegra = drm->dev_private;
        struct tegra_display_hub *hub = tegra->hub;
        struct tegra_shared_plane *plane;
@@ -797,6 +798,7 @@ struct drm_plane *tegra_shared_plane_create(struct 
drm_device *drm,
        }

drm_plane_helper_add(p, &tegra_shared_plane_helper_funcs);

+       drm_plane_create_blend_mode_property(p, blend_caps);
        drm_plane_create_zpos_property(p, 0, 0, 255);

return p;

Tested-by: Jon Hunter <jonath...@nvidia.com>
Acked-by: Jon Hunter <jonath...@nvidia.com>

Thanks!
Jon

--
nvpublic