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 650BDC433FE for ; Fri, 30 Sep 2022 15:37:11 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A3A7410ED5F; Fri, 30 Sep 2022 15:37:10 +0000 (UTC) Received: from mail-lf1-x12a.google.com (mail-lf1-x12a.google.com [IPv6:2a00:1450:4864:20::12a]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1998810ED5E; Fri, 30 Sep 2022 15:37:08 +0000 (UTC) Received: by mail-lf1-x12a.google.com with SMTP id 10so7468132lfy.5; Fri, 30 Sep 2022 08:37:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:message-id:subject:cc:to:from :date:from:to:cc:subject:date; bh=xHA6yjSDnlUKmhAAm+/NkiOEJECwwsljnyj0Tr5kTMg=; b=QiGgE06+RyoCdlUmQCnZpayta9xx+Qfnz6gcAAdHbJQ9cj8GkxR7HCnzFboDrKw2Sy 2kS4kd33v/oIIzYPAPb3CyR2rB2J14jjQwSYfC0TPYtz221TKo+44v/Bhu2UJixUBvG5 ltz8Jh0NPFH/1FP4qDS9AI9G8+S0YdR8UdgWkaa68g0lh5eqEOfe/gRTk/q3jtNm0sXL DL87pzi2XE4WDlORzNbbz4z6yGrjK48LjMEapFRhO5W2Z+SMhrFXlcS/5hDNuIJaU6di xc/PgnpZW4S+TVa4ynrB6jnJMMLjEEZNPgd/5UJjAdXCbWt9JjaOdhT+5OJae5899LLc iUUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=mime-version:references:in-reply-to:message-id:subject:cc:to:from :date:x-gm-message-state:from:to:cc:subject:date; bh=xHA6yjSDnlUKmhAAm+/NkiOEJECwwsljnyj0Tr5kTMg=; b=tm59Oua7+BVPq96izUuW4jEIHNz3zKuEmpfvpVDO63cbTsN8M9puE9LvsDYwpB/YYB nhNCyNq2aRg0eJLaEvIEEmrP0qnDl4OgC7z0b6fYUKz7vdXfD7eI6N00gbcCUkEtsmTe qrL7cMHbLhWJQ+zyNB/pB4QWnYwhTtN+nRg2d4XYC8GUF/4eC3yGhP/2g0IjUcawzw0S fYl6/BeMCtoJ7pU4SQPXz5RHUyl1uYCwHqn9kUFB9+cK5TpP6R5fDgNQl0nex7Pf8BDy U84rH4XdddKieoYM48oBU4D4E5sZfRbSC8du5A7RqAGX5kTaYUM+xM//jZvwPBJq2/P2 46+w== X-Gm-Message-State: ACrzQf3npnmN4+AW/jLLWn6IFQihJr59bwZstmKI3fbQCrK0hujkNbKr YTraRlusHZir+eByaJVV6eE= X-Google-Smtp-Source: AMsMyM5lPPWqtBjFAwl9uWSIpF+cvjWIxv7wpbd3IrAeRhhdrKlxDI9KTkSHNm+Vgd5fJOZ42fJdfw== X-Received: by 2002:a05:6512:370c:b0:49f:c4fb:8706 with SMTP id z12-20020a056512370c00b0049fc4fb8706mr3637748lfr.635.1664552226329; Fri, 30 Sep 2022 08:37:06 -0700 (PDT) Received: from eldfell ([194.136.85.206]) by smtp.gmail.com with ESMTPSA id q7-20020a0565123a8700b0048aef1abb08sm316410lfu.297.2022.09.30.08.37.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 30 Sep 2022 08:37:06 -0700 (PDT) Date: Fri, 30 Sep 2022 18:37:00 +0300 From: Pekka Paalanen To: Ville =?UTF-8?B?U3lyasOkbMOk?= Subject: KMS atomic state sets, full vs. minimal (Re: [PATCH v3 0/6] Add support for atomic async page-flips) Message-ID: <20220930183700.6cf64900@eldfell> In-Reply-To: References: <20220929184307.258331-1-contact@emersion.fr> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: multipart/signed; boundary="Sig_/T1hLgOzt2hE1JJTqqfx/6Yb"; protocol="application/pgp-signature"; micalg=pgp-sha256 X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: andrealmeid@igalia.com, Simon Ser , dri-devel@lists.freedesktop.org, wayland-devel@lists.freedesktop.org, mwen@igalia.com, amd-gfx@lists.freedesktop.org, daniel.vetter@ffwll.ch, alexander.deucher@amd.com, hwentlan@amd.com, nicholas.kazlauskas@amd.com, joshua@froggi.es Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" --Sig_/T1hLgOzt2hE1JJTqqfx/6Yb Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Fri, 30 Sep 2022 18:09:55 +0300 Ville Syrj=C3=A4l=C3=A4 wrote: > That would actively discourage people from even attempting the > "just dump all the state into the ioctl" approach with async flips > since even the props whose value isn't even changing would be rejected. About that. To me it looks like just a classic case of broken communication. The kernel developers assume that of course userspace will minimize the state set to only those properties that change, because...? Userspace developers think that of course the kernel will optimize the state set into minimal changes, because the kernel actually has the authoritative knowledge of what the current state is, and the driver actually knows which properties are costly and need to be optimized and which ones don't matter. It has never even occurred to me that the kernel would not compare next state to current state. No-one ever documented any expectations, did they? Thanks, pq --Sig_/T1hLgOzt2hE1JJTqqfx/6Yb Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEJQjwWQChkWOYOIONI1/ltBGqqqcFAmM3DRwACgkQI1/ltBGq qqflGA/+PFqtfhRFLCw87GGx+SNFRVQLLF975O0Zi3YnMfvmTh4ER4bfxasLoB+i KdEKxfDZflcisTrV306Gr9sc+sfvyyj5iXBWY1VEoX8wID3qh5lMW8ByE8ffgFpE pfGtTDs0Dfw2YoAfudnti92zlD7vdaaSkfOLeL/39/l0MyDVbKGfLJ2jha7WXsgc sknageMgRC1Agra5vAin222V05Xd0UpbBdb6cLkG7kfntdSzNYcJqpDSVfyNLw5u LkJvHaJtDK0KhLL+GYWxBkblQ4ykrQ60E4ZEnv/+rjhpGACEew96WJbLtj8ICVxg YT8o+ZBVWu3/PWJH9HZndL3uPBqpNcyYtOEfd5oPIz30Ow2vPy0w8TIf+vAjpBUw i3pI6SyWr/gPmnHS7xCIiUrDChxURblD68x8WCv8ynUVBh/agCTZGzHizIwGgyQ3 QiVlYJRqpKtrB6hdXOgoqC5jjItz+USXaw7+vuerYXpqkJfYhEgYmHuBp8WR98+x Pt16NGemdBUZ1DwrgctyvqDnFjPGOaiBVuYKle2UpNgsrRwdW5COE43ctceJUJoy NmS368bGoVF3Puh2673E33DG1APZQoIkBNjgQVFI2WZGhFL6NqNicG2GFQaBDukv IljNu5pp92fTpoCzcPo9CDhPEKt2bAnZ6CH4Bb4zobx7SHD0Qsw= =jhbY -----END PGP SIGNATURE----- --Sig_/T1hLgOzt2hE1JJTqqfx/6Yb-- 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 C82B1C4332F for ; Fri, 30 Sep 2022 15:37:14 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9F72310ED60; Fri, 30 Sep 2022 15:37:12 +0000 (UTC) Received: from mail-lf1-x12a.google.com (mail-lf1-x12a.google.com [IPv6:2a00:1450:4864:20::12a]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1998810ED5E; Fri, 30 Sep 2022 15:37:08 +0000 (UTC) Received: by mail-lf1-x12a.google.com with SMTP id 10so7468132lfy.5; Fri, 30 Sep 2022 08:37:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:message-id:subject:cc:to:from :date:from:to:cc:subject:date; bh=xHA6yjSDnlUKmhAAm+/NkiOEJECwwsljnyj0Tr5kTMg=; b=QiGgE06+RyoCdlUmQCnZpayta9xx+Qfnz6gcAAdHbJQ9cj8GkxR7HCnzFboDrKw2Sy 2kS4kd33v/oIIzYPAPb3CyR2rB2J14jjQwSYfC0TPYtz221TKo+44v/Bhu2UJixUBvG5 ltz8Jh0NPFH/1FP4qDS9AI9G8+S0YdR8UdgWkaa68g0lh5eqEOfe/gRTk/q3jtNm0sXL DL87pzi2XE4WDlORzNbbz4z6yGrjK48LjMEapFRhO5W2Z+SMhrFXlcS/5hDNuIJaU6di xc/PgnpZW4S+TVa4ynrB6jnJMMLjEEZNPgd/5UJjAdXCbWt9JjaOdhT+5OJae5899LLc iUUw== X-Google-DKIM-Signature: v=1; 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Fri, 30 Sep 2022 08:37:06 -0700 (PDT) Date: Fri, 30 Sep 2022 18:37:00 +0300 From: Pekka Paalanen To: Ville =?UTF-8?B?U3lyasOkbMOk?= Subject: KMS atomic state sets, full vs. minimal (Re: [PATCH v3 0/6] Add support for atomic async page-flips) Message-ID: <20220930183700.6cf64900@eldfell> In-Reply-To: References: <20220929184307.258331-1-contact@emersion.fr> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: multipart/signed; boundary="Sig_/T1hLgOzt2hE1JJTqqfx/6Yb"; protocol="application/pgp-signature"; micalg=pgp-sha256 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: andrealmeid@igalia.com, dri-devel@lists.freedesktop.org, wayland-devel@lists.freedesktop.org, mwen@igalia.com, amd-gfx@lists.freedesktop.org, daniel.vetter@ffwll.ch, alexander.deucher@amd.com, hwentlan@amd.com, nicholas.kazlauskas@amd.com, joshua@froggi.es Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" --Sig_/T1hLgOzt2hE1JJTqqfx/6Yb Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Fri, 30 Sep 2022 18:09:55 +0300 Ville Syrj=C3=A4l=C3=A4 wrote: > That would actively discourage people from even attempting the > "just dump all the state into the ioctl" approach with async flips > since even the props whose value isn't even changing would be rejected. About that. To me it looks like just a classic case of broken communication. The kernel developers assume that of course userspace will minimize the state set to only those properties that change, because...? Userspace developers think that of course the kernel will optimize the state set into minimal changes, because the kernel actually has the authoritative knowledge of what the current state is, and the driver actually knows which properties are costly and need to be optimized and which ones don't matter. It has never even occurred to me that the kernel would not compare next state to current state. No-one ever documented any expectations, did they? Thanks, pq --Sig_/T1hLgOzt2hE1JJTqqfx/6Yb Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEJQjwWQChkWOYOIONI1/ltBGqqqcFAmM3DRwACgkQI1/ltBGq qqflGA/+PFqtfhRFLCw87GGx+SNFRVQLLF975O0Zi3YnMfvmTh4ER4bfxasLoB+i KdEKxfDZflcisTrV306Gr9sc+sfvyyj5iXBWY1VEoX8wID3qh5lMW8ByE8ffgFpE pfGtTDs0Dfw2YoAfudnti92zlD7vdaaSkfOLeL/39/l0MyDVbKGfLJ2jha7WXsgc sknageMgRC1Agra5vAin222V05Xd0UpbBdb6cLkG7kfntdSzNYcJqpDSVfyNLw5u LkJvHaJtDK0KhLL+GYWxBkblQ4ykrQ60E4ZEnv/+rjhpGACEew96WJbLtj8ICVxg YT8o+ZBVWu3/PWJH9HZndL3uPBqpNcyYtOEfd5oPIz30Ow2vPy0w8TIf+vAjpBUw i3pI6SyWr/gPmnHS7xCIiUrDChxURblD68x8WCv8ynUVBh/agCTZGzHizIwGgyQ3 QiVlYJRqpKtrB6hdXOgoqC5jjItz+USXaw7+vuerYXpqkJfYhEgYmHuBp8WR98+x Pt16NGemdBUZ1DwrgctyvqDnFjPGOaiBVuYKle2UpNgsrRwdW5COE43ctceJUJoy NmS368bGoVF3Puh2673E33DG1APZQoIkBNjgQVFI2WZGhFL6NqNicG2GFQaBDukv IljNu5pp92fTpoCzcPo9CDhPEKt2bAnZ6CH4Bb4zobx7SHD0Qsw= =jhbY -----END PGP SIGNATURE----- --Sig_/T1hLgOzt2hE1JJTqqfx/6Yb--