From 38e0c3df6dbd36e69d38f67853cdd1bb6110d05f Mon Sep 17 00:00:00 2001 From: Leo Li Date: Mon, 26 Feb 2024 16:56:49 -0500 Subject: drm/amd/display: Move PRIMARY plane zpos higher [Why] Compositors have different ways of assigning surfaces to DRM planes for render offloading. It may decide between various strategies: overlay, underlay, or a mix of both (see here for more info: https://gitlab.freedesktop.org/emersion/libliftoff/-/issues/76) One way for compositors to implement the underlay strategy is to assign a higher zpos to the DRM_PRIMARY plane than the DRM_OVERLAY planes, effectively turning the DRM_OVERLAY plane into an underlay plane. Today, amdgpu attaches an immutable zpos of 0 to the DRM_PRIMARY plane. This however, is an arbitrary restriction. DCN pipes are general purpose, and can be arranged in any z-order. To support compositors using this allocation scheme, we can set a non-zero immutable zpos for the PRIMARY, allowing the placement of OVERLAYS (mutable zpos range 0-254) beneath the PRIMARY. [How] Assign a zpos = #no of OVERLAY planes to the PRIMARY plane. Then, clean up any assumptions in the driver of PRIMARY plane having the lowest zpos. v2: Fix typo s/decending/descending/ Reviewed-by: Harry Wentland Acked-by: Zaeem Mohamed Signed-off-by: Leo Li Acked-by: Pekka Paalanen Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher --- .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) (limited to 'drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c') diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c index 3e467244ad07..bb534b2b0b71 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c @@ -104,8 +104,6 @@ void amdgpu_dm_plane_fill_blending_from_plane_state(const struct drm_plane_state *global_alpha = false; *global_alpha_value = 0xff; - if (plane_state->plane->type == DRM_PLANE_TYPE_PRIMARY) - return; if (plane_state->pixel_blend_mode == DRM_MODE_BLEND_PREMULTI || plane_state->pixel_blend_mode == DRM_MODE_BLEND_COVERAGE) { @@ -1701,6 +1699,7 @@ int amdgpu_dm_plane_init(struct amdgpu_display_manager *dm, int res = -EPERM; unsigned int supported_rotations; uint64_t *modifiers = NULL; + unsigned int primary_zpos = dm->dc->caps.max_slave_planes; num_formats = amdgpu_dm_plane_get_plane_formats(plane, plane_cap, formats, ARRAY_SIZE(formats)); @@ -1730,10 +1729,19 @@ int amdgpu_dm_plane_init(struct amdgpu_display_manager *dm, } if (plane->type == DRM_PLANE_TYPE_PRIMARY) { - drm_plane_create_zpos_immutable_property(plane, 0); + /* + * Allow OVERLAY planes to be used as underlays by assigning an + * immutable zpos = # of OVERLAY planes to the PRIMARY plane. + */ + drm_plane_create_zpos_immutable_property(plane, primary_zpos); } else if (plane->type == DRM_PLANE_TYPE_OVERLAY) { - unsigned int zpos = 1 + drm_plane_index(plane); - drm_plane_create_zpos_property(plane, zpos, 1, 254); + /* + * OVERLAY planes can be below or above the PRIMARY, but cannot + * be above the CURSOR plane. + */ + unsigned int zpos = primary_zpos + 1 + drm_plane_index(plane); + + drm_plane_create_zpos_property(plane, zpos, 0, 254); } else if (plane->type == DRM_PLANE_TYPE_CURSOR) { drm_plane_create_zpos_immutable_property(plane, 255); } -- cgit v1.2.3