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From:   Emil Velikov <emil.l.velikov@gmail.com>
Date:   Thu, 31 May 2018 15:51:37 +0100
Message-ID: <CACvgo52NznSOWNvB_uOT4iQ-8+3A=ohhBe2os+jbEc=8pswn3A@mail.gmail.com>
Subject: Re: [PATCH v2 1/2] drm/blend: Add per-plane pixel blend mode property
To:     Lowry Li <lowry.li@arm.com>
Cc:     Liviu Dudau <liviu.dudau@arm.com>, David Airlie <airlied@linux.ie>,
        "Linux-Kernel@Vger. Kernel. Org" <linux-kernel@vger.kernel.org>,
        ML dri-devel <dri-devel@lists.freedesktop.org>,
        Mali DP Maintainers <malidp@foss.arm.com>,
        "Vetter, Daniel" <daniel.vetter@intel.com>, nd@arm.com
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Hi Lowry,

Small drive-by suggestion. Haven't checked if others have pointed it
out previously :-\

On 30 May 2018 at 12:23, Lowry Li <lowry.li@arm.com> wrote:

> +/**
> + * drm_plane_create_blend_mode_property - create a new blend mode property
> + * @plane: drm plane
> + * @supported_modes: bitmask of supported modes, must include
> + *                  BIT(DRM_MODE_BLEND_PREMULTI)
> + *
There are two possible blend modes (ignoring 'none'), yet premult must
be supported.
What if the hardware can do only "coverage"?

One-liner explaining why things are as-is would be a great move.

HTH
Emil