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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 5BDC9C48BE0 for ; Fri, 11 Jun 2021 12:56:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 435DE613D3 for ; Fri, 11 Jun 2021 12:56:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231251AbhFKM6X (ORCPT ); Fri, 11 Jun 2021 08:58:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33856 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231196AbhFKM6W (ORCPT ); Fri, 11 Jun 2021 08:58:22 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AEF29C061574 for ; Fri, 11 Jun 2021 05:56:24 -0700 (PDT) Received: from maud (unknown [IPv6:2600:8800:8c04:8c00::6334]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: alyssa) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id EAA2F1F4468F; Fri, 11 Jun 2021 13:56:09 +0100 (BST) Date: Fri, 11 Jun 2021 08:56:04 -0400 From: Alyssa Rosenzweig To: Liviu Dudau Cc: Simon Ser , Daniel Vetter , Maxime Ripard , Xinliang Liu , dri-devel , Anitha Chrisanthus , Jonathan Hunter , Jerome Brunet , Kevin Hilman , Ludovic Desroches , NXP Linux Team , Sascha Hauer , Roland Scheidegger , Sean Paul , Hyun Kwon , Andrew Jeffery , Seung-Woo Kim , Noralf Tr??nnes , Pengutronix Kernel Team , Alex Deucher , Laurent Pinchart , Alexandre Belloni , Linux Doc Mailing List , David Airlie , Edmund Dea , Thierry Reding , Daniel Vetter , Krzysztof Kozlowski , Steven Price , VMware Graphics , Ben Skeggs , Martin Blumenstingl , Rodrigo Siqueira , Boris Brezillon , Sandy Huang , Kyungmin Park , Maxime Coquelin , Haneen Mohammed , Neil Armstrong , Melissa Wen , Gerd Hoffmann , Benjamin Gaignard , Sam Ravnborg , Jonathan Corbet , Xinwei Kong , Chen-Yu Tsai , Alyssa Rosenzweig , Joel Stanley , Chun-Kuang Hu , Jonas Karlman , Chen Feng , Alison Wang , Rodrigo Vivi , Tomeu Vizoso , Tomi Valkeinen , Kieran Bingham , Tian Tao , Shawn Guo , Christian K??nig , Alexandre Torgue , Paul Cercueil , Andrzej Hajda , Huang Rui , Marek Vasut , Joonyoung Shim , Oleksandr Andrushchenko , Russell King , Philippe Cornu , Thomas Zimmermann , Hans de Goede , Matthias Brugger , Jernej Skrabec , Yannick Fertr e , Nicolas Ferre , Robert Foss , Qiang Yu , Jyri Sarha Subject: Re: [PATCH v3] Documentation: gpu: Mention the requirements for new properties Message-ID: References: <20210610174731.1209188-1-maxime@cerno.tech> <20210611120309.2b5eb4htupv5ss32@e110455-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210611120309.2b5eb4htupv5ss32@e110455-lin.cambridge.arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org > What I'm expected to see in the future is new functionality that gets implemented by > one hardware vendor and the kernel developers trying to enable that for userspace. It > could be that the new property is generic, but there is no way of testing that on > more than one implementation yet, so I'd say we are generous calling it "standard > property". When the second or third hardware vendor comes along and starts supporting > that property with their own set of extra requirements, then we can call it > "standard". Then comes the effort cost: would it be easier to start with a vendor > property that only the vendor needs to support (and can submit patches into the > compositors to do so) and when the standard property gets added moves to that, or > should we start with a generic property that gets implemented by the compositors > (maybe, but then only one vendor supports it) and then later when we actually > standardise the property we will have to carry backwards compatibility code in the > kernel to handle the old behaviour for old userspace? My proposal to Maxime was for > the former option to be reflected in the documentation, but I would like to hear your > thoughts. Just my 2c - if the mainline kernel isn't willing to commit to a feature for upstream userspace to use, why does that feature belong in the kernel at all? I don't see much value in exposing hardware for the sake of exposing it when, practically, Linux userspace /can't/ use it as-is. Might these vendor properties be used on downstream Android userspaces? That's not generally an upstream goal to support.