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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 A518AC282DA for ; Wed, 17 Apr 2019 14:03:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7E513206BA for ; Wed, 17 Apr 2019 14:03:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732351AbfDQODO (ORCPT ); Wed, 17 Apr 2019 10:03:14 -0400 Received: from relay9-d.mail.gandi.net ([217.70.183.199]:51849 "EHLO relay9-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731743AbfDQODN (ORCPT ); Wed, 17 Apr 2019 10:03:13 -0400 X-Originating-IP: 90.88.160.238 Received: from aptenodytes (aaubervilliers-681-1-42-238.w90-88.abo.wanadoo.fr [90.88.160.238]) (Authenticated sender: paul.kocialkowski@bootlin.com) by relay9-d.mail.gandi.net (Postfix) with ESMTPSA id BCEC5FF814; Wed, 17 Apr 2019 14:03:08 +0000 (UTC) Message-ID: <6b4d5c3bd1a6f58ce21bc79518e72ec00a1eed97.camel@bootlin.com> Subject: Re: [PATCH 06/20] lib: Add video format information library From: Paul Kocialkowski To: Maxime Ripard Cc: Daniel Vetter , David Airlie , Maarten Lankhorst , Sean Paul , Mauro Carvalho Chehab , Sakari Ailus , Hans Verkuil , Laurent Pinchart , Thomas Petazzoni , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org Date: Wed, 17 Apr 2019 16:03:08 +0200 In-Reply-To: <20190417124833.psdri6laune5y2ti@flea> References: <7dbdcb1b54a442e2d77a34bd449b52bbaf903157.camel@bootlin.com> <20190417124833.psdri6laune5y2ti@flea> Organization: Bootlin Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.32.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Wed, 2019-04-17 at 14:48 +0200, Maxime Ripard wrote: > Hi, > > On Wed, Apr 17, 2019 at 02:34:54PM +0200, Paul Kocialkowski wrote: > > > +struct image_format_info { > > > + union { > > > + /** > > > + * @drm_fmt: > > > + * > > > + * DRM 4CC format identifier (DRM_FORMAT_*) > > > + */ > > > + u32 drm_fmt; > > > > Could we call this one format_drm for consistency with the one below? > > The deprecated "format" field will go away at some point, so I'm not > sure the consistency is an argument there. Fair enough then. My point was mostly about format vs fmt, so one option could be to use "compat_fmt" or such, but do whatever you feel is right, I don't care too much about it. > > > +/** > > > + * image_format_info_min_pitch - computes the minimum required pitch in bytes > > > + * @info: pixel format info > > > + * @plane: plane index > > > + * @buffer_width: buffer width in pixels > > > + * > > > + * Returns: > > > + * The minimum required pitch in bytes for a buffer by taking into consideration > > > + * the pixel format information and the buffer width. > > > + */ > > > +static inline > > > +uint64_t image_format_info_min_pitch(const struct image_format_info *info, > > > + int plane, unsigned int buffer_width) > > > +{ > > > + if (!info || plane < 0 || plane >= info->num_planes) > > > + return 0; > > > + > > > + return DIV_ROUND_UP_ULL((u64)buffer_width * info->char_per_block[plane], > > > + image_format_info_block_width(info, plane) * > > > + image_format_info_block_height(info, plane)); > > > > I'm not sure I understand how this works: char_per_block is 0 for > > almost all formats and this doesn't take in account the cpp. Am I > > missing something here? > > I guess it doesn't. That's the DRM function here, without any > modification, but from a quick look at the current users of that > function, there's nobody that uses the value directly. > > So you might be right there. > > > Also, this might be a good occasion to discuss what meaning we want to > > give "stride" and "pitch": should one be in bytes and the other in bit, > > etc? I keep forgetting what each API expects. > > pitch is documented as bytes, and the function computing the stride I > added did too. I'll remove the stride one. Okay, it seems that I was just confused for no particular reason and stride, pitch, bytesperline and linesize are all just synonyms. So feel free to pick whichever you see fit :) Cheers, Paul -- Paul Kocialkowski, Bootlin Embedded Linux and kernel engineering https://bootlin.com