Re: [PATCH v4 0/2] drm/drm_blend: allow blend mode property without PREMULTI

From: Pekka Paalanen

Date: Tue Jun 16 2026 - 06:24:58 EST


On Tue, 26 May 2026 15:16:58 -0300
Leandro Ribeiro <leandro.ribeiro@xxxxxxxxxxxxx> wrote:

> Some hardware only supports the COVERAGE blend mode and lacks PREMULTI
> support entirely. DRM currently requires that PREMULTI is present when
> creating a blend mode property, which prevents such drivers from being
> properly upstreamed.
>
> This series removes this restriction and allows drivers to create a blend
> mode property without PREMULTI.
>
> On Weston (userspace), we are working [1] towards adding support for
> this kind of hardware.
>
> [1] https://gitlab.freedesktop.org/wayland/weston/-/merge_requests/2046

Hi,

the series is:

Acked-by: Pekka Paalanen <pekka.paalanen@xxxxxxxxxxxxx>

Thanks.

>
> v4:
> - Trigger warnings instead of errors when pixel format with alpha is
> exposed but blend mode is not setup.
> - Require blend mode only when plane exposes pixel formats with alpha, not
> when it supports the alpha property.
>
> v3:
> - Changed where we enforce drivers to expose blend mode for planes that
> support the alpha property or pixel formats with alpha.
> - Fixed missing check to forbid calling
> drm_plane_create_blend_mode_property() with a zero bitmask of
> supported modes.
>
> v2:
> - Force drivers to expose blend mode if plane supports alpha property
> or pixel format with alpha.
>
> Leandro Ribeiro (2):
> drm/drm_blend: allow blend mode property without PREMULTI
> drm: ensure blend mode supported if pixel format with alpha exposed
>
> drivers/gpu/drm/drm_blend.c | 20 ++++++++++++++------
> drivers/gpu/drm/drm_mode_config.c | 21 +++++++++++++++++++++
> 2 files changed, 35 insertions(+), 6 deletions(-)
>

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