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=-1.8 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 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 3342BC3815B for ; Fri, 17 Apr 2020 09:05:15 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 06D51221E9 for ; Fri, 17 Apr 2020 09:05:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="qm0t239P" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 06D51221E9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7C9636E3D8; Fri, 17 Apr 2020 09:05:13 +0000 (UTC) Received: from mail-lj1-x243.google.com (mail-lj1-x243.google.com [IPv6:2a00:1450:4864:20::243]) by gabe.freedesktop.org (Postfix) with ESMTPS id E86436E3D8 for ; Fri, 17 Apr 2020 09:05:12 +0000 (UTC) Received: by mail-lj1-x243.google.com with SMTP id u15so1263027ljd.3 for ; Fri, 17 Apr 2020 02:05:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version; bh=e8kOpv98LzmKW3f6/Aqb5L7ubDGfPOnZg7un0agq4Dc=; b=qm0t239P6LTCOVyXcUzlduSsLPtycQ7oACPeMWcpdrHT9xG551Yh/vgI/4thIxjBg7 +nFtnvSaseHVvkhvXtObbCHyJa3XUrGv3Fx69yuB4uJAFBBpu+2yfl/JGZ8K6+UWbBF7 jQjsXizyYeJE2khSW9s8zpxxREntHBteM9LZ3nef0vORwDpAxF8DIaSxGubW5mLbtlvB ubuOE2cG7JINBnecwkUBrGopLv7B8iJFlwdDzMkGfiueZ9Umnnfrvx0nXI0kby2QFpoc ffGC7OvYTAZMzxQ+SFq14fptzrMGIYFZl2NygGpTvfkiFEXlIQQL77qR7vgWDY3t9U9d t2Vg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version; bh=e8kOpv98LzmKW3f6/Aqb5L7ubDGfPOnZg7un0agq4Dc=; b=PyjVvEzmZXkPHq1HJLW0O+d4bQt0PdKxkoNjIhkrkByhbcf+6EumPFfWVy7euTGlsk 7G6gBi3AE7FQT9F9trSNCPg6dPWzXHZESDM2iaufuonMgAjUKSrzthbA/WeBxIp+pgIP X6DNpOoJkVfaFhmSWu9K9DhfacfuPmXVCdVPqLlTk/N6QLhefKIysD5t1IMbXGs76F14 i8nLYJuEqDgnmuPcv1KRcxxenV+uVTi4nBgnsma6kLlfbp9//seqp+2/xC7C7yGSzuVR FC/wYvzAU6uRQThm/PbZGdVuYHNNvnS2R9Vd6FNzUPlYNJYPRO9esTjZiX5859n2sQf2 ayBQ== X-Gm-Message-State: AGi0PuZdo0siunzt1e58xcsWs9KHptrNRcDYZI7uvBHU8Cn3LpWnUcH7 QC2uy6nS/zxZxhN2glGljEU= X-Google-Smtp-Source: APiQypJ515wp178XFYQNpV7+xTTqEqWrVKMz5i7KIwQviT+gbXm81ZF+LYsSeslKy2t9oh6HfVWWeA== X-Received: by 2002:a2e:994a:: with SMTP id r10mr1497730ljj.105.1587114311236; Fri, 17 Apr 2020 02:05:11 -0700 (PDT) Received: from eldfell.localdomain ([194.136.85.206]) by smtp.gmail.com with ESMTPSA id y199sm17594854lfa.80.2020.04.17.02.05.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 17 Apr 2020 02:05:10 -0700 (PDT) Date: Fri, 17 Apr 2020 12:05:06 +0300 From: Pekka Paalanen To: Rajat Jain , Hans de Goede , Mark Pearson Subject: Re: RFC: Drm-connector properties managed by another driver / privacy screen support Message-ID: <20200417120506.16db8df9@eldfell.localdomain> In-Reply-To: <87pnc84frl.fsf@intel.com> References: <783240e9-e8d1-fc28-6c11-14c8f8e35cfa@redhat.com> <87tv1k4vl6.fsf@intel.com> <87pnc84frl.fsf@intel.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 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: , Cc: Benjamin Berg , David Airlie , Christian Kellner , Javier Martinez Canillas , "dri-devel@lists.freedesktop.org" , Thomas Zimmermann , Nitin Joshi1 Content-Type: multipart/mixed; boundary="===============2006245895==" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" --===============2006245895== Content-Type: multipart/signed; micalg=pgp-sha256; boundary="Sig_/d0Z=XobJBDCcO6h7Krk2QRY"; protocol="application/pgp-signature" --Sig_/d0Z=XobJBDCcO6h7Krk2QRY Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Thu, 16 Apr 2020 00:10:06 +0300 Jani Nikula wrote: > On Wed, 15 Apr 2020, Rajat Jain wrote: > > * I think having 2 properties might be a confusing UAPI. Also, we have > > existing properties like link-status that can be changed by both the > > user and the hardware. =20 >=20 > I think the consensus is that all properties that get changed by both > userspace and the kernel are mistakes, and the way to handle it is to > have two properties. Yes, I very much agree with Jani. I don't like KMS properties that are writable by both the driver and userspace. It's awkward to handle in userspace and fundamentally racy aside from tricks like "what you wrote is not what you read back". I have ranted against that when looking at HDCP properties, e.g.: https://lists.freedesktop.org/archives/dri-devel/2019-July/226424.html See also my other email in this thread about how userspace uses atomic KMS UAPI: you must expect that userspace will always write the property for any KMS update, even if it does not change its value, so any change done by the kernel is randomly lost unless the property is read-only or otherwise weird. Thanks, pq --Sig_/d0Z=XobJBDCcO6h7Krk2QRY Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEJQjwWQChkWOYOIONI1/ltBGqqqcFAl6ZcUIACgkQI1/ltBGq qqf9EBAAok7A69ZnHeZlCAWyl90qov+2vdTMl0GFxBob7J3OHI8tNfAfCkMzMWRO Sf/mevhncofjOnZsTYE2rUBqlf+sazvyMnVQdSmkwIcIrcAnySwtHDBY3l184Xet vPuC9sLjR/uZvTN0ZndFR6PtZqu7CSB66UNWqAYHzWv+b5nBQi70g8/7dHl6KY+6 9xnZbac06pVKZRRjQJE13VkQoNOKiL6HEluEY1N5LY6+Pdn8N7jGaF6B2owSEfBh ev9ZAiHiAt0FiPEMsDVOD6WyI+Odl7D1uWREGnyl5wuoz5Q3aUINAblabuWCPkjz vBDD+YEll+Abgk3ztDq4aK0dujCKbZIY8BLQG7csTRT2FYVT+m52Sd2PH3+nZZGY dYg2cIT9kIRLjWG3zd84BJx5TwaRv9Z5JVCSs2RA8sWuKhOG04vMZzBCJ88Nt6qa tBpMLAetTjGukV3mLzhxICwNHcReZnC8URJpVb4wp4/niHgXYZYYm4gF4HXhVvpO 00v3oqHdQfkxusU9bSKf+iyVYXldhCDMk20bkoExtChlCQdGwxM+90bNBGlZU454 6Ihd+eH6W0BabjR2h8qQ2XFkVFcM3nWWWAqtmV+9KYZdBljAoz9kej3yjzb0vqhC i08yXs68GaQpmm3Pf53lDEWuhrFk/zr6t5nDLKM2/SpNedY0L68= =47GD -----END PGP SIGNATURE----- --Sig_/d0Z=XobJBDCcO6h7Krk2QRY-- --===============2006245895== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel --===============2006245895==--