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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A591C433EF for ; Mon, 8 Nov 2021 11:07:26 +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 239ED60ED7 for ; Mon, 8 Nov 2021 11:07:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 239ED60ED7 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=amd.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E627E6F4F8; Mon, 8 Nov 2021 11:07:24 +0000 (UTC) Received: from NAM10-DM6-obe.outbound.protection.outlook.com (mail-dm6nam10on2057.outbound.protection.outlook.com [40.107.93.57]) by gabe.freedesktop.org (Postfix) with ESMTPS id 212CC6F4ED for ; Mon, 8 Nov 2021 11:07:24 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=G/ViaW8lNNpihCCVCWSvxxGFBGHtvRiza5Fs4PNGblH5A450iDtFGlqF2cMa+XoxCdu9DJkp4or7YS9lhqTcogm4zu/wlCFimfEIgm9mVBNJfbX6WEO12lzttdBqK/Ec6OJ2piY7p6UQdcB9TGeDhkDZ2tlh/GsHelV8Kl8sPOlnmp/oDJ1dUEc3MgRie6Zx+RkOowiEYd0aLj4lxohkCAqneRcaL8xjDAh792c2qP2YIK1EnoKNqCjQDGQi9POY/2uDlFdRYiKqpzQ7Z8Dk7VYxdwFccaL7onPQ7RkdeAhVJYmYFQXYJSPBF4sqdAd73WDNp3s1/H6yzDtilQfuBA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=QaGirqbbEJtqjds+A26p5npYrlvT8fN6LRdwrWtT89I=; b=js7De5cpVXRhUTLKMqRhxzCNu6zTSNlxJjvEm9rHdXhP0jU1WIWLIYS9W+Wo0Ino1RKaL+IJIIkEL1FTtLT3ElEDr15KH+KAWzL/b7YVil9Om/op+zPsZ2XScJIAWuuK/C8uQUNLpStqgkZWfsrBd7e+w4EJezbYx1eloYM/o1zQJC4o+9TFne44HFM76AoSxW7Y4/T2fb/xAD53gOPpgzshBUMFgkf31A6u65EJB05HC6rX6eH3GCMG3p0fS2UAy8AZN92qMbL3F3Ok0dNDdVJKt+j1vU10nsi1cObI+iEp5pIqevZHlIEQSTKUhE7iKicNeVZADpCW3eSB1hr3ng== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amd.com; dmarc=pass action=none header.from=amd.com; dkim=pass header.d=amd.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=QaGirqbbEJtqjds+A26p5npYrlvT8fN6LRdwrWtT89I=; b=knTxai0XLhU5A2L/d3DeTv9bsKhuk8UCMupO0Sj31uh8zbIFETjzDH7klNTLElFfCOhZgsMTOSza3Q1ZhN5+oFuBW1CnpQ9BhoE9ohxuttg/t+JBpkk9EZJXdbI626iUpUnyepli4U4N8pOmJ18Fge9qA6buXvWB/00Y+rixSNI= Authentication-Results: linux.intel.com; dkim=none (message not signed) header.d=none;linux.intel.com; dmarc=none action=none header.from=amd.com; Received: from MWHPR1201MB0192.namprd12.prod.outlook.com (2603:10b6:301:5a::14) by MWHPR12MB1934.namprd12.prod.outlook.com (2603:10b6:300:109::23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4649.15; Mon, 8 Nov 2021 11:07:19 +0000 Received: from MWHPR1201MB0192.namprd12.prod.outlook.com ([fe80::2d02:26e7:a2d0:3769]) by MWHPR1201MB0192.namprd12.prod.outlook.com ([fe80::2d02:26e7:a2d0:3769%5]) with mapi id 15.20.4669.016; Mon, 8 Nov 2021 11:07:19 +0000 Subject: Re: [PATCH v2 6/6] drm/ttm: Clarify that the TTM_PL_SYSTEM buffers need to stay idle To: Zack Rusin , dri-devel@lists.freedesktop.org References: <20211105193845.258816-1-zackr@vmware.com> <20211105193845.258816-7-zackr@vmware.com> From: =?UTF-8?Q?Christian_K=c3=b6nig?= Message-ID: <3687c5f0-edb9-3cdb-2bb7-e45549a1cfb8@amd.com> Date: Mon, 8 Nov 2021 12:07:12 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 In-Reply-To: <20211105193845.258816-7-zackr@vmware.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-ClientProxiedBy: AM6P192CA0102.EURP192.PROD.OUTLOOK.COM (2603:10a6:209:8d::43) To MWHPR1201MB0192.namprd12.prod.outlook.com (2603:10b6:301:5a::14) MIME-Version: 1.0 Received: from [IPv6:2a02:908:1252:fb60:308a:d18e:268b:408f] (2a02:908:1252:fb60:308a:d18e:268b:408f) by AM6P192CA0102.EURP192.PROD.OUTLOOK.COM (2603:10a6:209:8d::43) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4669.16 via Frontend Transport; Mon, 8 Nov 2021 11:07:18 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 69e6246b-08d5-4b13-f6b7-08d9a2a7ee55 X-MS-TrafficTypeDiagnostic: MWHPR12MB1934: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:9508; X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:MWHPR1201MB0192.namprd12.prod.outlook.com; PTR:; CAT:NONE; SFS:(4636009)(366004)(31696002)(8936002)(45080400002)(8676002)(6666004)(5660300002)(86362001)(2906002)(83380400001)(4326008)(66574015)(186003)(31686004)(2616005)(38100700002)(66946007)(966005)(66556008)(6486002)(66476007)(36756003)(508600001)(316002)(45980500001)(43740500002); DIR:OUT; SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?S2ptUVcwS3U4MisrU1JhZ3lFWFp1ZTdYbE91TzBzNWkwRzh5bnVLb0V0UzFz?= =?utf-8?B?SGhyZXh4TlhyV1UyZitXRzFhOUkrOUlDMmluQk9ZeHgxVkRkSm9kTUcyTVFL?= =?utf-8?B?b1dxejFVdlNneDIyMTl2U2UyUFpEK1ZFR1hJTGN0NFIydFpFMVg2K2NYNXNB?= =?utf-8?B?aGRoWjRLZERjcS94OXdKMG53UFdRK3M0Yko3b2tPeU40aWJHNVFEZG82RWE3?= =?utf-8?B?eVhpUlZ3RmREQ1NEanVNNGxaalBZOEE1OFB5c2p1VllYZXQ4eGxCYzBwN0U1?= =?utf-8?B?SHRGN2VBUEdtZS9hZ2N2L2krcWdrQXdOS0xCM3BmbTNraHd2ZC9WT2ZMd0M2?= =?utf-8?B?VERQMTZHdzFsUEV0bzlHRzdCY2xMWE45aTloOW96bFc3YTRwYUZ5WWFOODJO?= =?utf-8?B?amNWWVE2WTZTMlVkK3dnWWE4V21rV1lOWnAwWWhJUnkzU3JGejM1NCt1akpI?= =?utf-8?B?bWFLTVNhRXA0NEZtUUxYTzFVYmVoY0NrYXAyL2d1ejFXVHlhZEFnTXFjbEN0?= =?utf-8?B?cmIvUldXaUJGSWFnSEkxRXdKOGp6UjhLeURxUTMvaC9YK3ZPQlBPZ1VBTXh5?= =?utf-8?B?ZlA2elQvclZLamgvOGc2MythQ2VuMlhXUHFLZXF6cXFUZFFvaGd1MVg2VGR3?= =?utf-8?B?NmdUUUhNZkRud3VHREVSZk9zcDdCR1JtaGRmczYvaEdUMENTUkxqVXdob0Uy?= =?utf-8?B?VnZURjZCdTFLbmRFZmJEZm9URzdERTE1SnVodVhQQXFIS2FsNVVicUkxMXBQ?= =?utf-8?B?K1NPQ2FOeGdwUVQ2QnN5K3F6a01uRUxIT2dnN1R0MGl3OWZ4V3NCQlBqMlZD?= =?utf-8?B?SmVhSzg1amd0VDRWM3V6akhXZHp2a1diZXl0YUZDMGw4bEpmR3JYS3dXekQx?= =?utf-8?B?M2d1K0srR2ErQ0U4OW05VzlIVUo1WWdUekFvaGt3N013QzhGdmNZc3RFL0l0?= =?utf-8?B?VTBQa3VBaVEzNm1nS2tPcWlUYXBpbjhzVDgzVzVxUFJPdThPMlRxMVNvV1pq?= =?utf-8?B?dkZQZ1RXMy9pUFJ2TXZKam5rTEN1Y2pBMUJzeDd5ZEtDMWpVRnRVRTNMTTFM?= =?utf-8?B?eXhxTmhXTFBpU3ZOc2oxRHNRR3JiTHB0ODA1dENTeEJ0Vi9DaHdPcm15KzZZ?= =?utf-8?B?MG9OSE5UZkZYT1Y0QlVQOXN2c2ZMWHJoSTVxUEIvK3JXWmJBVVhudThnVUV0?= =?utf-8?B?M2ZvbTV5ZWxvRTlNN1M5Y1ZWZUdhdzMydHVYS2ZTcEpsVmNtTUpMMk8wb3g0?= =?utf-8?B?ZlIyVDlrQlRUWGdpQi9xWW1lQ2VFbE05SDVyQ2ZqUFhiWktpSUVZMTNoV3R1?= =?utf-8?B?ZzZMeklZQTNUVUhLM3hjdWMwQnNia1pRcXFUeXZJTk4vVFhkMXA3L2p4R3R4?= =?utf-8?B?UzFHcWV5QjJ0bXNaZzg3QVhaS281WVFsTE9ycmdhSVU2U0Z3V1cwVGZSQ2JP?= =?utf-8?B?Z3ZmR3VWTnk4Zm9nRWNjRDJ5WTZQWnZObEV0bnhyV0xPS0VNOEwxbXdjaVQ4?= =?utf-8?B?cFE2TFZKQmJOL0JTTCtRL0tKZE51THhUZ1lwTGIrUDJTK1ZKMm1jdVRRcjJm?= =?utf-8?B?RExFN3lPSS9oajVTMU56RkwrMHpkZWR4TkxzQzF0S2dkV3dVZW50T3hPcVV0?= =?utf-8?B?RXhscmk2c3orMTlicGp3VmtOOU5EcklrVmxYVjN1Zy9SczRLaUxqR2R6UTFs?= =?utf-8?B?VmJwSEZQaTJVSW5tR3ExMzMxZTlrK05BYWVuS2ROMVhLU2xHekw1WlhWb2RJ?= =?utf-8?B?NHBQTndrOTRmUUh2TlVuQ0JuK01pYmQ3aUt4UzQ3Vk9jeURPZzhFV0FwTDY2?= =?utf-8?B?cURORVViR0RLYnNlQ1BKOTIrQlR4VkZhRTlCaXZPUXN6enVEMEVndlJNZzhn?= =?utf-8?B?RHowcGtzb3VYakx1ZCt6ZjZxWEhkRytPN3hqMTRmcXpFR2pVSzVlT2Q3Y3dV?= =?utf-8?B?K0trMDhMeDBDT2Y2c0hpc296c1BXTEhLTThkUU0xWkNMbDh3VlhrYWh0YktU?= =?utf-8?B?cUxUYzROMnRoMGdkakhEckNGMk00c1RDT0FVWVo5Y3dJTUlCL2Rock14VENm?= =?utf-8?B?UGxCa1ZpUzRtOVNhd00xNkJQa0o3YVUwZVZUenkrNk5GajdoVlNPcmdOR0h0?= =?utf-8?B?dFhlM3hmRUJLUUF2VXhHVUo3Z3ZXejZnUGlnT0o5N09lait5Q0QrTklXZ2Fv?= =?utf-8?Q?AYmWU7RLIFDMtxq8ghTon1Q=3D?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 69e6246b-08d5-4b13-f6b7-08d9a2a7ee55 X-MS-Exchange-CrossTenant-AuthSource: MWHPR1201MB0192.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Nov 2021 11:07:19.3644 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 6pDXa+W+Re7CdLxpoBtGSy92G8MoCesYBn1ml0AR7lu/uVTtBVMgpi9ENgC/Xhig X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR12MB1934 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: =?UTF-8?Q?Thomas_Hellstr=c3=b6m?= Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Am 05.11.21 um 20:38 schrieb Zack Rusin: > TTM was designed to allow TTM_PL_SYSTEM buffer to be fenced but over > the years the code that was meant to handle it was broken and new > changes can not deal with buffers which have been placed in TTM_PL_SYSTEM > buf do not remain idle. > CPU buffers which need to be fenced and shared with accelerators should > be placed in driver specific placements that can explicitly handle > CPU/accelerator buffer fencing. > Currently, apart, from things silently failing nothing is enforcing > that requirement which means that it's easy for drivers and new > developers to get this wrong. To avoid the confusion we can document > this requirement and clarify the solution. > > This came up during a discussion on dri-devel: > https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fdri-devel%2F232f45e9-8748-1243-09bf-56763e6668b3%40amd.com&data=04%7C01%7Cchristian.koenig%40amd.com%7C4f4ed0ab73894a482abd08d9a0942b98%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637717380521122147%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=1lGhEIESDwizXnC7APtlhGws8miB4xeh%2FsTewsEPfBY%3D&reserved=0 > > Signed-off-by: Zack Rusin > Cc: Christian König > Cc: Thomas Hellström > --- > include/drm/ttm/ttm_placement.h | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/include/drm/ttm/ttm_placement.h b/include/drm/ttm/ttm_placement.h > index 76d1b9119a2b..89dfb58ff199 100644 > --- a/include/drm/ttm/ttm_placement.h > +++ b/include/drm/ttm/ttm_placement.h > @@ -35,6 +35,16 @@ > > /* > * Memory regions for data placement. > + * > + * Due to the fact that TTM_PL_SYSTEM BO's can be accessed by the hardware > + * and are not directly evictable they're handled slightly differently > + * from other placements. The most important and driver visible side-effect > + * of that is that TTM_PL_SYSTEM BO's are not allowed to be fenced and have > + * to remain idle. For BO's which reside in system memory but for which > + * the accelerator requires direct access (i.e. their usage needs to be > + * synchronized between the CPU and accelerator via fences) a new, driver > + * private placement should be introduced that can handle such scenarios. > + * That we don't have fences on them is just the tip on the iceberg and mostly nice to have. The major problem is that TTM_PL_SYSTEM are considered under TTMs control and swapped out whenever TTMs thinks it is a good idea. That needs to be handled manually in the driver if a TTM_PL_SYSTEM is ever considered a valid placement. Christian. > */ > > #define TTM_PL_SYSTEM 0