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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1F9E8EE49A5 for ; Mon, 21 Aug 2023 20:02:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230170AbjHUUCr (ORCPT ); Mon, 21 Aug 2023 16:02:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58850 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230153AbjHUUCq (ORCPT ); Mon, 21 Aug 2023 16:02:46 -0400 Received: from fanzine2.igalia.com (fanzine2.igalia.com [213.97.179.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DFC2F11C for ; Mon, 21 Aug 2023 13:02:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=rkMx3QCdkHsHd4DpWtJVECdQPGcyggajnYUXBpzw15w=; b=EADq7rmE7GqaIGEfqJn7DfTL3f iUjUJxP8Z7CSXigjq1oBS+lwDFwrd9pB8nLZ0Zd3NomDntKyrh6JK4n6CQ0H9E2kQ8JWFqqNCIfoi eGKuHptuFiQFRX9LF7zoq5Y0RDMqBuYiUPRFqkq1vn5sqRUx2MAYqLAiqKPwEKeJIIp4FBXQ99219 ZTUvafOEKXg0/qQJrFvCQdQqKTKx0sVsQMtfhGupKHTwzMO9o3SukOrG7Y8rymsrWKdtwIL+vI6dB Nf5x9UYvna/0pmr6EpwUPHBhJSJs/51aCCC86e/yVptlesZGhKHfjYnh8HRHdsp+JSNt/4D7OxDdC 9OsMhXtg==; Received: from [187.35.42.59] (helo=[192.168.1.111]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_128_GCM:128) (Exim) id 1qYB6X-00DrMF-0V; Mon, 21 Aug 2023 22:02:25 +0200 Message-ID: Date: Mon, 21 Aug 2023 17:02:19 -0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 6/6] drm/doc: Define KMS atomic state set To: =?UTF-8?Q?Michel_D=C3=A4nzer?= Cc: pierre-eric.pelloux-prayer@amd.com, amd-gfx@lists.freedesktop.org, Pekka Paalanen , linux-kernel@vger.kernel.org, Daniel Vetter , =?UTF-8?B?J01hcmVrIE9sxaHDoWsn?= , Randy Dunlap , Pekka Paalanen , dri-devel@lists.freedesktop.org, Daniel Stone , hwentlan@amd.com, Rob Clark , wayland-devel@lists.freedesktop.org, ville.syrjala@linux.intel.com, kernel-dev@igalia.com, alexander.deucher@amd.com, Dave Airlie , christian.koenig@amd.com, joshua@froggi.es References: <20230815185710.159779-1-andrealmeid@igalia.com> <20230815185710.159779-7-andrealmeid@igalia.com> <1b23576d-1649-ff5c-6273-b54729ea46d8@mailbox.org> Content-Language: en-US From: =?UTF-8?Q?Andr=C3=A9_Almeida?= In-Reply-To: <1b23576d-1649-ff5c-6273-b54729ea46d8@mailbox.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Michel, Em 17/08/2023 07:37, Michel Dänzer escreveu: > On 8/15/23 20:57, André Almeida wrote: >> From: Pekka Paalanen >> >> Specify how the atomic state is maintained between userspace and >> kernel, plus the special case for async flips. >> >> Signed-off-by: Pekka Paalanen >> Signed-off-by: André Almeida > > [...] > >> +An atomic commit with the flag DRM_MODE_PAGE_FLIP_ASYNC is allowed to >> +effectively change only the FB_ID property on any planes. No-operation changes >> +are ignored as always. [...] > > During the hackfest in Brno, it was mentioned that a commit which re-sets the same FB_ID could actually have an effect with VRR: It could trigger scanout of the next frame before vertical blank has reached its maximum duration. Some kind of mechanism is required for this in order to allow user space to perform low frame rate compensation. > I believe the documentation already addresses that sending redundant information may not lead to the desired behavior during an async flip. Do you think adding a note about using the same FB_ID would be helpful?