From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) (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 E6FD3220689 for ; Fri, 25 Apr 2025 10:18:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.251.105.195 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745576324; cv=none; b=VC2+bVrN/BuCcbKukwmTPOgkqfPtdzhkq6IZuCv5LtDjAguUMtiYvFyEwYGW6yG+Hyzg/XJyjCOOeToahbqt98xUj3HQUtTrpFLAaKjikkx/qSEodh+pmaGIaXTDeWJc1xZvdNsmJGyIZNq6HoPmqGbRhJR3ggnUiHvgjFkavN4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745576324; c=relaxed/simple; bh=+WMDRHwIxjNdFWZib1N8x93fRIjfmI7anWK8oxtytUg=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=sKgwk6OUbI7hg4c61yonjzK7N6EEioxrhk1orCtIHnqW0kFovkFUX1dEfpwZvRayQF3P3Lsiso+IdyTy5X6TX5eY4UfsyqeB4TJ+09dpRKaCuMz9fYPtxTHdRcUdgU2PNzb6GXphBfkXZuIRQVGOWasXwlFz/6C+C1zrBzx42k4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=fS8OBStg; arc=none smtp.client-ip=148.251.105.195 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="fS8OBStg" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1745576318; bh=+WMDRHwIxjNdFWZib1N8x93fRIjfmI7anWK8oxtytUg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=fS8OBStgXmEHPXUtgkQM6i6oldyGjHhVXAffJrz40OrrJDixFwzubm2Jjg2v2cmUv LmnmNqmFur9E5HCtxdfibtsa36Vxyr+lqMpHBeDveVhs5fy0gzCs33TzLPPMof0iw4 ylrUroQH9zIEk5hXM3LaumCgjzrFtrshAOKLj5zW5YghhblY17lEoGLTUcdSfVYaV0 EXmuYNQYKhv0cRLgc+ntPLmiHduEjMltKTcEDNshKbQKBpkrggTkKwLq+n9vOLU3Ky C7Ad1vqexnj6rH7xkvQOSaU0XBCmXcaei5EN+/YyIst8AG3onO9rnByzIXpJuk8wc7 VmN2qkPkqiYTQ== Received: from eldfell (unknown [194.136.85.206]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: pq) by bali.collaboradmins.com (Postfix) with ESMTPSA id 4D41617E0F66; Fri, 25 Apr 2025 12:18:38 +0200 (CEST) Date: Fri, 25 Apr 2025 13:18:17 +0300 From: Pekka Paalanen To: Tomi Valkeinen Cc: Laurent Pinchart , Geert Uytterhoeven , Vishal Sagar , Anatoliy Klymenko , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Michal Simek , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Dmitry Baryshkov Subject: Re: [PATCH v4 03/11] drm/fourcc: Add DRM_FORMAT_Y8 Message-ID: <20250425131817.01b7f7d9@eldfell> In-Reply-To: References: <20250326-xilinx-formats-v4-0-322a300c6d72@ideasonboard.com> <20250326-xilinx-formats-v4-3-322a300c6d72@ideasonboard.com> <20250327112009.6b4dc430@eldfell> <20250327175842.130c0386@eldfell> <20250331105446.098f0fbe@eldfell> <20250331082135.GB13690@pendragon.ideasonboard.com> <20250331135337.61934003@eldfell> <20250401162732.731ef774@eldfell> <73bd6628-374d-417f-a30f-88a4b1d157bb@ideasonboard.com> <20250417111315.62a749e5@eldfell> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; boundary="Sig_/+HlgRhuvMGsiYHXtWjVBSQu"; protocol="application/pgp-signature"; micalg=pgp-sha256 --Sig_/+HlgRhuvMGsiYHXtWjVBSQu Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Fri, 25 Apr 2025 11:38:28 +0300 Tomi Valkeinen wrote: > Hi Pekka, >=20 > On 17/04/2025 11:13, Pekka Paalanen wrote: > >> My understanding is that the Y-only pixel formats behave in a well > >> defined way (or, as well defined as the YUV formats), and there's > >> nothing more to add here. Is that right? =20 > >=20 > > There are two things: > >=20 > > - Y8 follows COLOR_RANGE property, just like all other YUV formats. > > - Y8 implies that Cb and Cr are both neutral (0.0 in nominal values). > >=20 > > I'd like these explicitly written down, so that they become obvious to > > everyone. I suspect either one might be easy to forget when writing > > code and taking shortcuts without thinking. =20 >=20 > I didn't find a suitable place in the docs for this, but would this, in=20 > the drm_fourcc.h, be enough: >=20 > /* > * Y-only (greyscale) formats > * > * The Y-only formats are handled similarly to the YCbCr formats in the= =20 > display > * pipeline, with the Cb and Cr implicitly neutral (0.0 in nominal=20 > values). This > * also means that COLOR_RANGE property applies to the Y-only formats. > * > */ >=20 > #define DRM_FORMAT_Y8 fourcc_code('G', 'R', 'E', 'Y') /* 8-bit Y-only */ > #define DRM_FORMAT_Y10_P32 fourcc_code('Y', 'P', 'A', '4') /* [31:0]=20 > x:Y2:Y1:Y0 2:10:10:10 little endian */ >=20 Hi Tomi, I would be very happy with that. 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