Public Hey Melissa,
I've found out that this patch causes some IGT failures with the igt@kms_plane_alpha_blend tests. I noticed it with a RX 7900 XT on a 4k60 HP U27. The tests fail with an assertion failure. I posted a snippet below. Starting subtest: alpha-basic Starting dynamic subtest: pipe-A-DP-1 [181.052561] (kms_plane_alpha_blend:9570) igt_kms-CRITICAL: Test assertion failure function do_display_commit, file ../lib/igt_kms.c:4982: [181.052564] (kms_plane_alpha_blend:9570) igt_kms-CRITICAL: Failed assertion: ret == 0 [181.052568] (kms_plane_alpha_blend:9570) igt_kms-CRITICAL: Last errno: 22, Invalid argument [181.052571] (kms_plane_alpha_blend:9570) igt_kms-CRITICAL: error: -22 != 0 Dynamic subtest pipe-A-DP-1 failed. Thank you, Dan Wheeler Sr. Technologist | AMD SW Display ------------------------------------------------------------------------------------------------------------------ 1 Commerce Valley Dr E, Thornhill, ON L3T 7X6 amd.com -----Original Message----- From: amd-gfx <[email protected]> On Behalf Of Melissa Wen Sent: Tuesday, August 4, 2026 10:01 AM To: [email protected]; Deucher, Alexander <[email protected]>; Koenig, Christian <[email protected]>; [email protected]; Wentland, Harry <[email protected]>; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; Li, Sun peng (Leo) <[email protected]>; [email protected] Cc: Hung, Alex <[email protected]>; [email protected]; Lyude Paul <[email protected]>; [email protected]; [email protected] Subject: [PATCH v2 2/3] drm/amd/display: fix missing blend-mode-prop warning for DCN validate_blend_mode_for_alpha_formats() warns when a plane supports formats with alpha but doesn't expose the blend mode property. Fix this by adding the same overlay plane blend modes to primary plane, since they are all universal planes in DCN-generation. Cursor planes support ARGB8888 format and CURSOR_MODE_COLOR_PRE_MULTIPLIED_ALPHA is set by default (other color formats are not implemented), so only expose support to PREMULTI, which is the default blend mode on DRM. Fixes: 860e748bddcc ("drm: ensure blend mode supported if pixel format with alpha exposed") Signed-off-by: Melissa Wen <[email protected]> --- .../amd/display/amdgpu_dm/amdgpu_dm_plane.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) 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 1b564cfe2120..a276f3730044 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 @@ -1923,8 +1923,15 @@ int amdgpu_dm_plane_init(struct amdgpu_display_manager *dm, if (res) return res; - if (plane->type == DRM_PLANE_TYPE_OVERLAY && - plane_cap && plane_cap->per_pixel_alpha) { + /* TODO: Check which blend modes are supported in DCE-generation + * planes, i.e. DC_PLANE_TYPE_DCE_RGB/UNDERLAY and expose blend mode + * property accordingly. + */ + if ((plane->type == DRM_PLANE_TYPE_OVERLAY || + plane->type == DRM_PLANE_TYPE_PRIMARY) && + plane_cap && + plane_cap->type == DC_PLANE_TYPE_DCN_UNIVERSAL && + plane_cap->per_pixel_alpha) { unsigned int blend_caps = BIT(DRM_MODE_BLEND_PIXEL_NONE) | BIT(DRM_MODE_BLEND_PREMULTI) | BIT(DRM_MODE_BLEND_COVERAGE); @@ -1933,6 +1940,13 @@ int amdgpu_dm_plane_init(struct amdgpu_display_manager *dm, drm_plane_create_blend_mode_property(plane, blend_caps); } + /* Cursor color format is set to CURSOR_MODE_COLOR_PRE_MULTIPLIED_ALPHA + * by default, so only advertise DRM_MODE_BLEND_PREMULTI blend mode for + * this type of plane. + */ + if (plane->type == DRM_PLANE_TYPE_CURSOR) + drm_plane_create_blend_mode_property(plane, +BIT(DRM_MODE_BLEND_PREMULTI)); + if (plane->type == DRM_PLANE_TYPE_PRIMARY) { /* * Allow OVERLAY planes to be used as underlays by assigning an -- 2.53.0
