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 X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D031BC282DA for ; Wed, 17 Apr 2019 13:13:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8FEA206BA for ; Wed, 17 Apr 2019 13:13:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732228AbfDQNNF (ORCPT ); Wed, 17 Apr 2019 09:13:05 -0400 Received: from relay12.mail.gandi.net ([217.70.178.232]:57265 "EHLO relay12.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731958AbfDQNNC (ORCPT ); Wed, 17 Apr 2019 09:13:02 -0400 Received: from localhost (aaubervilliers-681-1-42-238.w90-88.abo.wanadoo.fr [90.88.160.238]) (Authenticated sender: maxime.ripard@bootlin.com) by relay12.mail.gandi.net (Postfix) with ESMTPSA id 799ED200019; Wed, 17 Apr 2019 13:12:57 +0000 (UTC) Date: Wed, 17 Apr 2019 15:12:56 +0200 From: Maxime Ripard To: Maarten Lankhorst Cc: Daniel Vetter , David Airlie , Sean Paul , Mauro Carvalho Chehab , Sakari Ailus , Hans Verkuil , Laurent Pinchart , Thomas Petazzoni , Paul Kocialkowski , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, Emil Velikov Subject: Re: [PATCH 04/20] drm/fourcc: Pass the format_info pointer to drm_format_plane_width/height Message-ID: <20190417131256.s7dwk6cda5ezgedd@flea> References: <194fd02a37172de6f2a799fee5c98ced5e7e9d76.1555487650.git-series.maxime.ripard@bootlin.com> <776131c6-b8be-4302-ea9a-f7d84203f28c@linux.intel.com> <20190417110119.ygp6h7kpzzo5a27l@flea> <8d909dcf-16de-7462-1cc6-2713778ed8b1@linux.intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="kvnadm2bo6fe5gqf" Content-Disposition: inline In-Reply-To: <8d909dcf-16de-7462-1cc6-2713778ed8b1@linux.intel.com> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --kvnadm2bo6fe5gqf Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Apr 17, 2019 at 01:10:33PM +0200, Maarten Lankhorst wrote: > Op 17-04-2019 om 13:01 schreef Maxime Ripard: > > On Wed, Apr 17, 2019 at 12:47:48PM +0200, Maarten Lankhorst wrote: > >>> +/** > >>> + * drm_format_info_plane_width - width of the plane given the first plane > >>> + * @format: pixel format info > >>> + * @width: width of the first plane > >>> + * @plane: plane index > >>> + * > >>> + * Returns: > >>> + * The width of @plane, given that the width of the first plane is @width. > >>> + */ > >>> +static inline > >>> +int drm_format_info_plane_width(const struct drm_format_info *info, int width, > >>> + int plane) > >>> +{ > >>> + if (!info || plane >= info->num_planes) > >>> + return 0; > >>> + > >>> + if (plane == 0) > >>> + return width; > >>> + > >>> + return width / info->hsub; > >>> +} > >>> + > >>> +/** > >>> + * drm_format_info_plane_height - height of the plane given the first plane > >>> + * @format: pixel format info > >>> + * @height: height of the first plane > >>> + * @plane: plane index > >>> + * > >>> + * Returns: > >>> + * The height of @plane, given that the height of the first plane is @height. > >>> + */ > >>> +static inline > >>> +int drm_format_info_plane_height(const struct drm_format_info *info, int height, > >>> + int plane) > >>> +{ > >>> + if (!info || plane >= info->num_planes) > >>> + return 0; > >>> + > >>> + if (plane == 0) > >>> + return height; > >>> + > >>> + return height / info->vsub; > >>> +} > >> Why the null checks? None of the other inlines for drm_format_info > >> perform them. > > Unless I'm mistaken, the subsampling only applies to the planes with > > the chrominance, which are always >= 1. Therefore the plane 0 is > > always the luminance, to which the subsampling doesn't apply. > > > > Or are you talking about something else? > > > The info == NULL check. :) Aaah, sorry :) That's true, and that's actually the first four patches that change that behaviour a bit. Previously, drm_format_plane_cpp, _width, and _height will do the lookup themselves using drm_format_info, and test whether the pointer returned is null or not. Patches 3 and 4 removed that lookup but kept the null pointer check. We could remove it, but there's two downsides for that: * since the lookup is now effectively pushed to the caller (or the caller's caller), we would have to check there that the pointer isn't NULL. That's a lot of boilerplate to add. * And since this is a generic function, I wouldn't trust the caller to give a pointer that can be dereferenced right away. This might be more subjective though. So I guess we should make sure that we are consistent, but I'd be in favor of putting that check in all the functions. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --kvnadm2bo6fe5gqf Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCXLcmWAAKCRDj7w1vZxhR xaPNAP92L9ciIW3gEMnYB1PtGzfhqgemZhqKiIES5NyhTkygcwEA9u6+JtowTsyQ wYGHeFVWHijR1wqA+oxf1HcSl9D1FgQ= =uZbL -----END PGP SIGNATURE----- --kvnadm2bo6fe5gqf--