Since commit 860e748bddcc ("drm: ensure blend mode supported if pixel
format with alpha exposed"), drm_mode_config_validate() warns when a
plane exposes an alpha pixel format but not the "pixel blend mode"
property. The cursor (ARGB8888, all platforms) and the VLV/CHV primary
and sprite planes trip this.Userspace has historically assumed premultiplied blending when the property is not attached, so it is safe to assume that planes that did not expose the property already blended with fixed pre-multiplied alpha in hardware. Therefore, expose a "pixel blend mode" property advertising only DRM_MODE_BLEND_PREMULTI to match that assumption and silence the warning. The cursor call is unconditional; the primary and sprite calls are gated to VLV/CHV, the only platforms whose format lists include alpha formats. Assisted-by: Claude:claude-opus-4-8 Cc: Ville Syrjälä <[email protected]> Cc: Uma Shankar <[email protected]> Cc: Leandro Ribeiro <[email protected]> Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/work_items/16623 Signed-off-by: Chaitanya Kumar Borah <[email protected]> --- drivers/gpu/drm/i915/display/i9xx_plane.c | 4 ++++ drivers/gpu/drm/i915/display/intel_cursor.c | 3 +++ drivers/gpu/drm/i915/display/intel_sprite.c | 4 ++++ 3 files changed, 11 insertions(+) diff --git a/drivers/gpu/drm/i915/display/i9xx_plane.c b/drivers/gpu/drm/i915/display/i9xx_plane.c index 70734d32a409..490908f59141 100644 --- a/drivers/gpu/drm/i915/display/i9xx_plane.c +++ b/drivers/gpu/drm/i915/display/i9xx_plane.c @@ -1108,6 +1108,10 @@ intel_primary_plane_create(struct intel_display *display, enum pipe pipe) DRM_MODE_ROTATE_0, supported_rotations); + if (display->platform.valleyview || display->platform.cherryview) + drm_plane_create_blend_mode_property(&plane->base, + BIT(DRM_MODE_BLEND_PREMULTI)); + zpos = 0; drm_plane_create_zpos_immutable_property(&plane->base, zpos); diff --git a/drivers/gpu/drm/i915/display/intel_cursor.c b/drivers/gpu/drm/i915/display/intel_cursor.c index 88384dea868b..0673f16f6fd0 100644 --- a/drivers/gpu/drm/i915/display/intel_cursor.c +++ b/drivers/gpu/drm/i915/display/intel_cursor.c @@ -1078,6 +1078,9 @@ intel_cursor_plane_create(struct intel_display *display, intel_cursor_add_size_hints_property(cursor); + drm_plane_create_blend_mode_property(&cursor->base, + BIT(DRM_MODE_BLEND_PREMULTI)); + zpos = DISPLAY_RUNTIME_INFO(display)->num_sprites[pipe] + 1; drm_plane_create_zpos_immutable_property(&cursor->base, zpos); diff --git a/drivers/gpu/drm/i915/display/intel_sprite.c b/drivers/gpu/drm/i915/display/intel_sprite.c index 6a65f92e8a03..3e38960bbbd8 100644 --- a/drivers/gpu/drm/i915/display/intel_sprite.c +++ b/drivers/gpu/drm/i915/display/intel_sprite.c @@ -1722,6 +1722,10 @@ intel_sprite_plane_create(struct intel_display *display, DRM_COLOR_YCBCR_BT709, DRM_COLOR_YCBCR_LIMITED_RANGE); + if (display->platform.valleyview || display->platform.cherryview) + drm_plane_create_blend_mode_property(&plane->base, + BIT(DRM_MODE_BLEND_PREMULTI)); + zpos = sprite + 1; drm_plane_create_zpos_immutable_property(&plane->base, zpos); -- 2.25.1
