From nobody Fri Sep 20 01:19:52 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4371F17B02C for ; Wed, 10 Jul 2024 08:52:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720601575; cv=none; b=BkOGnFwyTZxDGEWXzYG2UGnjsHX6DUnHhKnHOKOoS3jckDbmBdoLVxHXKlDusWyE9GcyKFqus+mSBOw+6jH7/IcFYZP19kklxjNdvHtS5eDexIJ87hSjW6EqJgRBADWSBhX6zyr/JrT1+M+81Xy2bvXdUJveXIgiwgX8KL+wa3E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720601575; c=relaxed/simple; bh=fyYXOHu9fHp+yDLi4tjopWasn0OOj6F3xVVYEta73ZQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=QcmIMcbvo0dfo0r4D+n9H2hXNZivhQ1booeUOLe3c18w3mQKY0gfg3zXlq1wDQ2PVJ1P8mjcwd2w/K7pMa8g4c6lZaNfVsByUosQvnP/4ldkPrMz0AKB6r0TFOc6W1snuTaIq8gPDRjoMvROM8A9jHt5ecyILTweb4by67zr118= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=agMy0ZvP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="agMy0ZvP" Received: by smtp.kernel.org (Postfix) with ESMTPS id C59D8C4AF10; Wed, 10 Jul 2024 08:52:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720601574; bh=fyYXOHu9fHp+yDLi4tjopWasn0OOj6F3xVVYEta73ZQ=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=agMy0ZvPA9AgNZn1oouu2BL7h3fSH1dC8oL5gaXTLb8jDdc/L42xSzg+NrzwpoUUW YdabgmkExMiNXy91Ea3vTUyGEsWCAYoA3sqOOWIKG4sQyXHDKyrvkGjnBqQe5qjQtN 7p8ut5y5CI8kU3wr0hKevB9DD26v7OlgJdcwHG1Unkb7TOldNZ01vnFEc2rBOiJZZy AG+WqHyKIOHS1vP6M0AJ8C7TOSOQYWSRT1SxjBXZHJkibj8T9P3UtLo+U8eBZfji3l YeI1WtHI9mHaQK/VXMP/OolrCaxWW544ZB1rXEqc17aYcJSd1GV4GG0doP6Hbt+jLc DAhFACn2Fj50g== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id BDA44C3DA45; Wed, 10 Jul 2024 08:52:54 +0000 (UTC) From: Hsiao Chien Sung via B4 Relay Date: Wed, 10 Jul 2024 16:52:55 +0800 Subject: [PATCH v3 5/5] drm/mediatek: Support alpha blending in display driver Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20240710-alpha-blending-v3-5-289c187f9c6f@mediatek.com> References: <20240710-alpha-blending-v3-0-289c187f9c6f@mediatek.com> In-Reply-To: <20240710-alpha-blending-v3-0-289c187f9c6f@mediatek.com> To: Chun-Kuang Hu , Philipp Zabel , David Airlie , Daniel Vetter , Matthias Brugger , AngeloGioacchino Del Regno Cc: dri-devel@lists.freedesktop.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Hsiao Chien Sung , CK Hu , Hsiao Chien Sung X-Mailer: b4 0.14.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1720601573; l=2210; i=shawn.sung@mediatek.com; s=20240710; h=from:subject:message-id; bh=NXMVY+5up48Xsv5+9pKY3kYmUYHXnlx5rItB6cJy0f4=; b=g2exBNCESLyv0OqJnjsb6aEiZ7/B0/C+zT6GweHyHS0nO0LEBQ6E0tfIYh3ix4JSSOu48bEH2 rlbJA5vUiPpA+rpTx5lzAlHRI6UtPp/+0gK9zVNnmvBcw/enxuJI6jE X-Developer-Key: i=shawn.sung@mediatek.com; a=ed25519; pk=VRlGZ3diQkQtpDd8fCL9/mx+TpZStm08pg8UPaG1NGc= X-Endpoint-Received: by B4 Relay for shawn.sung@mediatek.com/20240710 with auth_id=184 X-Original-From: Hsiao Chien Sung Reply-To: shawn.sung@mediatek.com From: Hsiao Chien Sung Support "Pre-multiplied" and "None" blend mode on MediaTek's chips by adding correct blend mode property when the planes init. Before this patch, only the "Coverage" mode (default) is supported. For more information, there are three pixel blend modes in DRM driver: "None", "Pre-multiplied", and "Coverage". To understand the difference between these modes, let's take a look at the following two approaches to do alpha blending: 1. Straight: dst.RGB =3D src.RGB * src.A + dst.RGB * (1 - src.A) This is straightforward and easy to understand, when the source layer is compositing with the destination layer, it's alpha will affect the result. This is also known as "post-multiplied", or "Coverage" mode. 2. Pre-multiplied: dst.RGB =3D src.RGB + dst.RGB * (1 - src.A) Since the source RGB have already multiplied its alpha, only destination RGB need to multiply it. This is the "Pre-multiplied" mode in DRM. For the "None" blend mode in DRM, it means the pixel alpha is ignored when compositing the layers, only the constant alpha for the composited layer will take effects. Reviewed-by: CK Hu Reviewed-by: AngeloGioacchino Del Regno Signed-off-by: Hsiao Chien Sung --- drivers/gpu/drm/mediatek/mtk_plane.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/gpu/drm/mediatek/mtk_plane.c b/drivers/gpu/drm/mediate= k/mtk_plane.c index 1723d4333f37..5bf757a3ef20 100644 --- a/drivers/gpu/drm/mediatek/mtk_plane.c +++ b/drivers/gpu/drm/mediatek/mtk_plane.c @@ -346,6 +346,17 @@ int mtk_plane_init(struct drm_device *dev, struct drm_= plane *plane, DRM_INFO("Create rotation property failed\n"); } =20 + err =3D drm_plane_create_alpha_property(plane); + if (err) + DRM_ERROR("failed to create property: alpha\n"); + + err =3D drm_plane_create_blend_mode_property(plane, + BIT(DRM_MODE_BLEND_PREMULTI) | + BIT(DRM_MODE_BLEND_COVERAGE) | + BIT(DRM_MODE_BLEND_PIXEL_NONE)); + if (err) + DRM_ERROR("failed to create property: blend_mode\n"); + drm_plane_helper_add(plane, &mtk_plane_helper_funcs); =20 return 0; --=20 2.43.0