From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from DM5PR21CU001.outbound.protection.outlook.com (mail-centralusazon11011043.outbound.protection.outlook.com [52.101.62.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0212D3D8123; Tue, 25 Aug 2026 21:13:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.62.43 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787692424; cv=fail; b=hNZ5yi+or8mgxKaSGGI3QnxesgxJjhIzVZMqcWzbMgZ58WVhB0OJVEQwUqhInK5Fi/Iy8Mr2ktxdD68LvUfOGTQZCnZ0Y0VlVgh88migumEC6FxaHuxb48D7JB63HCQH0dPlDCTxxXR3zIV9pRUCsAjErMHqVo2tJeLoTPXdCLw= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787692424; c=relaxed/simple; bh=nYSygfPBGLPHXpGlc0WUfHQVKG1lijx4nda49eV3jeI=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=B9ogRp71cz9F1ljyXU+LTu3+rGigYA1dW15kcPcejXTa8aoKUdADL00pE6MHgTXICb802SjgBpyV9IUSC+JOBSiMD+ZkAr3IzQ9rn5mYhUSRn61MN1OLOphIRAc50cY3av+I/BnJSw2uQ9yBYCCU/AIFTY8SHyafEJeEft8ozAc= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=KIO5VB/X; arc=fail smtp.client-ip=52.101.62.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="KIO5VB/X" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=BDe1GfTSBpheKxNCcLTp1KjTPLxDlQoIF4nYNtk13wCKT2x5TX9FjZ/yidXnsE40AAiU2wldyaz/dsv1pMjNrbxTqQcMxWvKr3mpVdRAqDTcRCAD5eRNKF8xSr7Z2ccH/dqYr+/nrQS2zSo/FiQIxrpyKhXce100Ub88vL1Gez0u2MtiU/duUyopeHlEWwCebublOb/oP8f457Ls9L1bEpcdPYQqRYP6RBNg5sJ1m2njxBrd+cf6ZtyH+1lloE68ZEY1s/M+7V47ZNZF3t7sefz410SXTZdxWX57JjQuhU/b/SpEAz7z7YMdJCdFnFD1j9bZJqxOrMPDZm2Nk8icRw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; 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=UtBBfdQ9wl//E3dPMvOJnhbv5IMdEDbpNcJudAL7sD0=; b=ob2tPmUGX/R9Wi0XInDv+X/CJXLkZHPNK/2SrgIJuVktLypAbbROByf2zqJRPHDr5xeP2UUcDvBATR57KyuyqYxmZgblw/tbmBYUWI8HdjNdAmimCSpguTIMYW7YmGobnxXZNOqT5wN6Bv0s4B1vz1vxAOgjaSqROeiVANClhntnZq14ENP5LlZ8SSHwQdZ0whisa9RKLOVtomP71KFY1gtj4RVEZYGuIvWk9M2CNbgybUJiB48gzlqEoqLSVXRYXcoBF2POv0mZsPGHqC7ghshilkTp2mtsVnPagHdOC2f+XjSVLZ6RlE3V5pmOpCAIZa/NcmSQEK4PE68Ae/MHQw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=UtBBfdQ9wl//E3dPMvOJnhbv5IMdEDbpNcJudAL7sD0=; b=KIO5VB/X2CsXqwAkP+arHQIK2Py1xu5nnSyQEXiGF/gO/xjQ5AkvaUPcH5nCFDn72DZVDxHqgLpvVldRWZmnizNYNAQm5afTAAH6gPvbxZlIOVRpG4+u1DfM+mJeyAYoATT8WHShfuc5MCv14YAanBoT9sqx8dEs1P2JAjfArHtufKN1LhOkVTs0q0ikqoI1JSGBwF7yzDOp7vbsgiMXQscymzWE0b7R+XYJtE/P8mGbA0xUPaycpBdBQ9O5iAVOSzlYUmrAB3FtdYf4HPdH7CEKRJtrVMeME9mA3/jlylobEklJdAeymb7J3tNLOzw4RRaso60MoVmjYGmeoC3wcw== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DM3PR12MB9416.namprd12.prod.outlook.com (2603:10b6:0:4b::8) by SJ2PR12MB8882.namprd12.prod.outlook.com (2603:10b6:a03:537::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.339.12; Tue, 25 Aug 2026 21:13:36 +0000 Received: from DM3PR12MB9416.namprd12.prod.outlook.com ([fe80::8cdd:504c:7d2a:59c8]) by DM3PR12MB9416.namprd12.prod.outlook.com ([fe80::8cdd:504c:7d2a:59c8%4]) with mapi id 15.21.0339.012; Tue, 25 Aug 2026 21:13:35 +0000 Message-ID: Date: Tue, 25 Aug 2026 14:13:33 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 3/7] drm: nova: Add chipid enum to nova-drm UAPI To: Danilo Krummrich , Alistair Popple Cc: M Henning , nova-gpu , Alice Ryhl , David Airlie , Alexandre Courbot , Benno Lossin , Gary Guo , Eliot Courtney , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org References: <20260811050657.646799-1-apopple@nvidia.com> <20260811050657.646799-4-apopple@nvidia.com> Content-Language: en-US From: John Hubbard In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: BY5PR03CA0022.namprd03.prod.outlook.com (2603:10b6:a03:1e0::32) To DM3PR12MB9416.namprd12.prod.outlook.com (2603:10b6:0:4b::8) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM3PR12MB9416:EE_|SJ2PR12MB8882:EE_ X-MS-Office365-Filtering-Correlation-Id: 015a8cc9-54db-423a-5d80-08df02edb97a X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|1800799024|7416014|366016|23010399003|11063799006|10067099003|4143699003|6133799003|56012099006|18002099003|22082099003; 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:DM3PR12MB9416.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(1800799024)(7416014)(366016)(23010399003)(11063799006)(10067099003)(4143699003)(6133799003)(56012099006)(18002099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?U21zMDkwMi9kSk1HVjJFZHBKWW82V0trdDl3ZnpEZTdRU2ZUdW9tNFZRV2g4?= =?utf-8?B?UmpIMWJGcEdSY2VoTTE1d3U3bE5udlU3aDNISklKbzZjWnFSUHlDRjYyaFZX?= =?utf-8?B?M2V0eURFc2E0WlI0NllGZmR4M0hNNEIxeHd5WEt6S1BvZVlzVFE0eldZcmds?= =?utf-8?B?YzhSMlpDQk5CalRGTUdBMjlQZEVqekdQTkJXYk96VXBRN2ZiZk5DUDkyeFpT?= =?utf-8?B?MGtjOE5nRUc5c3QzeHNHNVlsM1hWNlR5VER6Nlk5WFpvUExuckVUdmxmWFpQ?= =?utf-8?B?eFpTMDR5STNmQUJxSm9qSEV6cFZyZDZlSzhXWG85c1F1VENvdjl2ZEhSMk9Z?= =?utf-8?B?b2toSWI2RExWcFhyRTd2VGJSSW1WRW1UdHowb251QWFqQzd3OSs2WU96RG1l?= =?utf-8?B?MThJNmVUR0pVZFN4aWxCTTVYU2owczJUS3FHL0hvZktYQ3N1YlNFSGIzc1dM?= =?utf-8?B?OVZoTXNhSE9xa0Y1Umx4M2ZQNm9NNU5Cc09QN1JZTGlOeFR1Mkd1M003WUs2?= =?utf-8?B?K3BONmZDS0Y1MDUwY0ZqREZLU2FrZU5jN3RUZjZobzJxMGVTeFh5bkF5RWE3?= =?utf-8?B?SlJFSDA3QzVkMExXWHNUUythbCtaQy9pR3pKNTN3VkZnZnlJc0o0TzlIM1BN?= =?utf-8?B?WW02dmR0d2Fhb3FHVkV4R3ZVbjhxRGx1Z0JPNHpRY2NYWFREclUyWC9Ia2RW?= =?utf-8?B?SzhYeHA3VnNvMGtuYnQ0MEtldCt3MTNWK2NQbExNRlp1Q3BwSm5CSW1CUmw3?= =?utf-8?B?MERoVXF4RUcxNmdrcTR3ZVdzMUtUSGt2dndlWHRrbUVKKytpanZGcDdqVnU0?= =?utf-8?B?c1J2WXJjSm5WcnhlL2Q0Rk5YdFk3amJrcGhyU1BHT3djUkRaSExWblNKR2o5?= =?utf-8?B?MlBtMElGeHRoY3JkSWJ1czNkai9GMjRZQ1J6UmF3OGFBZUNiNjNSUjN1RHRK?= =?utf-8?B?WUhadmc4WE1YaTYrLytCajhwV0FLT0lsVFdXalladXpoV2dZRWpPNVRKU1lH?= =?utf-8?B?YzlqU2l4Qk1hai9Wa1c2ODNHNisxUG5TcjBmTTZMLzdOazQyWHhXUk94MjZm?= =?utf-8?B?TU1HdE5UTHVqTExhUTUrQjcyWmRta0ZuY2dudE5nZk5hQW5QNzNrTEFGNTVG?= =?utf-8?B?aVY5OHIvdFpPS2ZwaFY3QjA1byt6L2l0eWJBejJubW1JNUdWbWhZdUU5RWtx?= =?utf-8?B?SG1XQXdlQU9EMGxMRkxIem1JMG85QThTTjh4Q1BkNmFuZWxlQ0lpWWh4RGZZ?= =?utf-8?B?SkRuM25PYUpKUUVTUjA0SFMrUUpta05td0d6c2J6QUJHL3lQcGdvRVgvZEVS?= =?utf-8?B?alMxV0pJZXEvTmhCNzF4NFRHMDMwSW1lbU5sTWpjMVQxMnlZYkQwYlcrRGFh?= =?utf-8?B?RWROQVd4QXRFRWlHd3BiSFlSYWhLQk1FZWYyQVlUbzYwWFE3Nloxb1FONG4y?= =?utf-8?B?MlYrNFlSTlozUjR2YnlJcDd2R2FQQnBYcktwRW9ham44UWtid2FORzIyQmUw?= =?utf-8?B?MS9vQ2dkMlhMWFdVTHZDM3h6VCtRSGpKMDhQQWpnbExnYzFNUFBDSU1kdkdJ?= =?utf-8?B?MUdsVE1wVlA2VVJpSkZTMmR0QU0zRDFNWlhlTHlkRTk3WC9iZ2Q2YXRlM3Nj?= =?utf-8?B?UlByZlAzTGpvc2NCUkJ4bEJ6QWMrQ29iLzVzWXFNdi9oTXdBK1pyMXd0OU4v?= =?utf-8?B?STFUdGNKcENEWlVrL3EzMU13RTNYZWdiMDArSUVHRWJqT2kreWtiRE9MaVR2?= =?utf-8?B?aXlqdHpxTUJLa21PNXRWV1ZSdDBYRGk3WTg0WHg1WWlidzhWTGlQU0lFdkhO?= =?utf-8?B?N0tHTndORkw4UUIwa0ZYMUowNUt1VmtvSndVd1VGSmNkRm5vamt3ajRGMXVY?= =?utf-8?B?Q0RuM1FLSHZPV1VST1dLSFltM3ZIZGFaRUg0Z2hybWZMSzdJTnpSaWpNWUFT?= =?utf-8?B?bFVEajRUclV6cFQyblZROG1iWUFNbmlUNXg5Q3cwaHFqMFZSMFU2dy9yUmxv?= =?utf-8?B?ZmlvOUNibDIzdXpuQmJiTlVPK09teE5hVEFzeEhVTnBTaGhwL3JIVUtLY1hL?= =?utf-8?B?SGJPbC81d0VNcU9hTmVSRzZzS3k1QXFNTjFlL0IyemZIQU1sN0ZscDJJQnVK?= =?utf-8?B?MVlIWWUrZklPc0VtVVF4K1d2NmpQVGMzRlpvZVFIdFlQTi9WN1hGM3lnbWdT?= =?utf-8?B?U05ReFNwdEdMRWhrcVY0M2dvb2M5QzhpSlVZWE5UQks3dkRxWWljV0EwcUhx?= =?utf-8?B?MnNYWEJwRlhQWksxTVl1Y2ttdXNlMUYyUm9hSmdLdkJWR21MYjViNHYwOW84?= =?utf-8?B?WkZkNnRzTmtxa1dLbnlJaVBKK24wU2dMclRMYi9vV2o2N1k1dmExZz09?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 015a8cc9-54db-423a-5d80-08df02edb97a X-MS-Exchange-CrossTenant-AuthSource: DM3PR12MB9416.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Aug 2026 21:13:35.4522 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: e5UKlWsrxms7ZjPiv37+QdLzRZnp49frhUSs2CtvPVBuTdB8zdz1s4wCxwhN8tAf8mMTHGenXuNOr3+OykOGog== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ2PR12MB8882 On 8/25/26 1:53 PM, Danilo Krummrich wrote: > On Tue Aug 25, 2026 at 9:13 AM CEST, Alistair Popple wrote: ...>> For example if someone plugs a shiny new card with a different chip_id >> register layout into a machine running an older kernel they could get an >> incorrect arch which would be confusing. Users would get upset if for example >> ShinyNewCard got reported as being Turing say. > > If the kernel can't deal with a chip it should never succeed probing and never > expose any information to userspace in the first place. Agreed. We had also some discussion about this point during the BOOT0/BOOT42 change-over. And we arrived at that same conclusion back then: don't let PCI probe succeed on an unknown new chip. > > nova-core does enforce this already; if a chipid can't be matched against an > architecture it won't compile, and if the chipid is not known by nova-core it > will fail to probe. > > Note that nova-core binds by vendor + class, not specific PCI device IDs, so the > chipset check is our only gate against unknown hardware. > > If we'd hypothetically remove that gate and just allow trying to probe unknown > hardware with the boot sequence of just assuming some default with the latest > supported architecture, it would potentially be an even worse user experience, > where instead of a clear rejection of the hardware a user might experience > security/stability issues. > >> So I think it makes sense to keep this decoding in user-space regardless of >> whether that's exposed via documented opaque chip IDs and lookup tables for >> arch/implementation or by a commitment to keep the chip ID register layout the >> same. > > I still don't see much value in letting userspace decode this again, nor do I > think lookup tables are necessary. > > If the driver succeeds to probe for a device we already did decode things, so > there's no need for userspace to do it again or know about this. Also agreed here. It's hard to see any advantage in decoding in both user space and kernel. thanks, -- John Hubbard