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=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 184E1C43387 for ; Fri, 21 Dec 2018 08:57:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB5E7218F0 for ; Fri, 21 Dec 2018 08:56:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388615AbeLUI46 (ORCPT ); Fri, 21 Dec 2018 03:56:58 -0500 Received: from mail.netline.ch ([148.251.143.178]:56924 "EHLO netline-mail3.netline.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388577AbeLUI44 (ORCPT ); Fri, 21 Dec 2018 03:56:56 -0500 Received: from localhost (localhost [127.0.0.1]) by netline-mail3.netline.ch (Postfix) with ESMTP id F406E2A6056; Fri, 21 Dec 2018 09:56:53 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at netline-mail3.netline.ch Received: from netline-mail3.netline.ch ([127.0.0.1]) by localhost (netline-mail3.netline.ch [127.0.0.1]) (amavisd-new, port 10024) with LMTP id iSKgIW2nQwOr; Fri, 21 Dec 2018 09:56:53 +0100 (CET) Received: from thor (39.1.199.178.dynamic.wline.res.cust.swisscom.ch [178.199.1.39]) by netline-mail3.netline.ch (Postfix) with ESMTPSA id 52E3B2A6055; Fri, 21 Dec 2018 09:56:53 +0100 (CET) Received: from localhost ([::1]) by thor with esmtp (Exim 4.91) (envelope-from ) id 1gaGc1-0001BQ-0l; Fri, 21 Dec 2018 09:56:53 +0100 Subject: Re: [PATCH 1/3] drm/amd: fix race in page flip job To: Yu Zhao , David Airlie , Daniel Vetter , =?UTF-8?Q?Christian_K=c3=b6nig?= , Alex Deucher Cc: David Zhou , Daniel Stone , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, Samuel Li , Junwei Zhang , Harry Wentland References: <20181221031053.240161-1-yuzhao@google.com> From: =?UTF-8?Q?Michel_D=c3=a4nzer?= Openpgp: preference=signencrypt Autocrypt: addr=michel@daenzer.net; prefer-encrypt=mutual; keydata= mQGiBDsehS8RBACbsIQEX31aYSIuEKxEnEX82ezMR8z3LG8ktv1KjyNErUX9Pt7AUC7W3W0b LUhu8Le8S2va6hi7GfSAifl0ih3k6Bv1Itzgnd+7ZmSrvCN8yGJaHNQfAevAuEboIb+MaVHo 9EMJj4ikOcRZCmQWw7evu/D9uQdtkCnRY9iJiAGxbwCguBHtpoGMxDOINCr5UU6qt+m4O+UD /355ohBBzzyh49lTj0kTFKr0Ozd20G2FbcqHgfFL1dc1MPyigej2gLga2osu2QY0ObvAGkOu WBi3LTY8Zs8uqFGDC4ZAwMPoFy3yzu3ne6T7d/68rJil0QcdQjzzHi6ekqHuhst4a+/+D23h Za8MJBEcdOhRhsaDVGAJSFEQB1qLBACOs0xN+XblejO35gsDSVVk8s+FUUw3TSWJBfZa3Imp V2U2tBO4qck+wqbHNfdnU/crrsHahjzBjvk8Up7VoY8oT+z03sal2vXEonS279xN2B92Tttr AgwosujguFO/7tvzymWC76rDEwue8TsADE11ErjwaBTs8ZXfnN/uAANgPLQjTWljaGVsIERh ZW56ZXIgPG1pY2hlbEBkYWVuemVyLm5ldD6IXgQTEQIAHgUCQFXxJgIbAwYLCQgHAwIDFQID AxYCAQIeAQIXgAAKCRBaga+OatuyAIrPAJ9ykonXI3oQcX83N2qzCEStLNW47gCeLWm/QiPY jqtGUnnSbyuTQfIySkK5AQ0EOx6FRRAEAJZkcvklPwJCgNiw37p0GShKmFGGqf/a3xZZEpjI qNxzshFRFneZze4f5LhzbX1/vIm5+ZXsEWympJfZzyCmYPw86QcFxyZflkAxHx9LeD+89Elx bw6wT0CcLvSv8ROfU1m8YhGbV6g2zWyLD0/naQGVb8e4FhVKGNY2EEbHgFBrAAMGA/0VktFO CxFBdzLQ17RCTwCJ3xpyP4qsLJH0yCoA26rH2zE2RzByhrTFTYZzbFEid3ddGiHOBEL+bO+2 GNtfiYKmbTkj1tMZJ8L6huKONaVrASFzLvZa2dlc2zja9ZSksKmge5BOTKWgbyepEc5qxSju YsYrX5xfLgTZC5abhhztpYhGBBgRAgAGBQI7HoVFAAoJEFqBr45q27IAlscAn2Ufk2d6/3p4 Cuyz/NX7KpL2dQ8WAJ9UD5JEakhfofed8PSqOM7jOO3LCA== Message-ID: <02562071-6010-7c49-fb82-aceaf24d877f@daenzer.net> Date: Fri, 21 Dec 2018 09:56:52 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 MIME-Version: 1.0 In-Reply-To: <20181221031053.240161-1-yuzhao@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-CA Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018-12-21 4:10 a.m., Yu Zhao wrote: > Fix race between page flip job submission and completion. We invoke > page_flip callback to submit page flip job to GPU first and then set > pflip_status. If GPU fires page flip done irq in between, its handler > won't see the correct pflip_status thus will refuse to notify the job > completion. The job will eventually times out. > > Reverse the order of calling page_flip and setting pflip_status to > fix the race. There is no race, amdgpu_crtc->pflip_status is protected by dev->event_lock. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer