From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A5772FF885D for ; Sun, 26 Apr 2026 16:59:30 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E494B10E25A; Sun, 26 Apr 2026 16:59:29 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=emersion.fr header.i=@emersion.fr header.b="Q2eC4HQL"; dkim-atps=neutral Received: from mail-4323.protonmail.ch (mail-4323.protonmail.ch [185.70.43.23]) by gabe.freedesktop.org (Postfix) with ESMTPS id 525D710E25A for ; Sun, 26 Apr 2026 16:59:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=emersion.fr; s=protonmail; t=1777222765; x=1777481965; bh=tUDUyDOnCOqPoW+O+WZwKRHRLeRqAPThkvPuVS5TBX0=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector; b=Q2eC4HQLRpZSF7fKkw2jeTRA1Grf+H9SotgXdn/xfVfVSyUsecMh2sbyIGhss4WJY 5I4FsFw9AiJLGyqQmU1GSKm4dryeO6FPDhNKD71NJSv5XGutGnnklgA0991Wq6mOYQ FL7W7+7JqeiiGkbTjwYmq5SbX1h8HZiJou6GU3fb0F2J3jRVc0nexq8MNKTk0L9zt4 xb2v7Ug7pxmgT0PkICq2Jy2dQIanD8cw/plhrDoFRzvnECLcTWSy8OigqVQhrCsm64 dAyc+5JCp5dzNOha/nMzdDTpcaLeQtOtPc0ewnm/TFgLt0WXsMig5fr9X7zXu3EoJm DBlJB0luLKVfw== Date: Sun, 26 Apr 2026 16:59:19 +0000 To: Laurent Pinchart From: Simon Ser Cc: dri-devel@lists.freedesktop.org, Pekka Paalanen , Tomi Valkeinen , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Dmitry Baryshkov , Daniel Stone Subject: Re: [PATCH] drm/fourcc: document format naming scheme Message-ID: In-Reply-To: <20260426164739.GE2964234@killaraus.ideasonboard.com> References: <20260426151641.93763-1-contact@emersion.fr> <20260426164739.GE2964234@killaraus.ideasonboard.com> Feedback-ID: 1358184:user:proton X-Pm-Message-ID: d48cc7349b6266edda2777ceda7e20e167f6ec78 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Sunday, April 26th, 2026 at 18:47, Laurent Pinchart wrote: > > + * Memory layout is always described in little-endian order. >=20 > This sentence may be a bit vague, especially given that we have the > DRM_FORMAT_BIG_ENDIAN() macro. Right, that macro is almost never used=E2=80=A6 I see it only used for XRGB1555 and RGB565. Someone recommended against using it, I don't remember who. See also: * Note that the DRM_FORMAT_BIG_ENDIAN flag should only be used in * case the format can't be specified otherwise, so we don't end up * with two values describing the same format. > > + * - The first digit indicates chroma sub-sampling: 0 for 2x2, 2 for 2= x1, 4 for > > + * none. >=20 > We also have 4x4 and 4x1 sub-sampled formats, it would be good to > document them. Yeah, but these use a completely different scheme, like the NV family. And then there's single-plane YUV formats, which are just the wild west. Not sure how to document all of that=E2=80=A6