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 9A57CEB64DA for ; Thu, 22 Jun 2023 16:33:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231157AbjFVQdk (ORCPT ); Thu, 22 Jun 2023 12:33:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229891AbjFVQdj (ORCPT ); Thu, 22 Jun 2023 12:33:39 -0400 Received: from NAM11-BN8-obe.outbound.protection.outlook.com (mail-bn8nam11on2040.outbound.protection.outlook.com [40.107.236.40]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0629D1BD9; Thu, 22 Jun 2023 09:33:38 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Lu5gSiN4QXkf6dai0UOR3rS/5mk5IPL8jkt+G5VM1E4QUaCUSYZU+pXttjj0eNXFxXdKxpo8QfPSbFI0NdJ4//x+94uINGWlp5i013c+TSGtcgtpEVFFwVEcdEKy30pYlyzP+gPc4AINXf/K+bGil9BCcRUOQiFCK8vdojqgCcCDFxyxIT3Ob92+OB9WasTXRcTRd/ln66BJ6L8q0qWhOkIIVvzEsa3KeYGKSeC99F4l1XBf5EuzOAWJk271nblcX+sMf22HhrZkdM1V/gIf63zwdiqJi2f4kPjOZ8RFTPXIk5gvfZnDkvyZNt+Mx89hYG4m5vhg/QdvIWUceWFA4g== 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=SBGRfS2nosjhf2Ap5cgALUDykFntsRi6zHaU+lQKCKw=; b=oF3HxA4YK+GIpERc4niKnhG/0mAwdrsUSnAT6cWX5vDG4EHEalJqCDT/zpLjyLuaFZ7e/mEUy91nOZyFdSn0aRqcKR5bosW8BFDtFJ80Es+QkrqmxHFohH9KBW5iobMlRu2RQS3kdsKIucqD6w1Jm61JxWXUzIlcdLMMrEtZiAZppd3bWFZFabpq6synjTDE5bx11FhNSS1aG2JW0CdKf7I2y+Xqs++mNQtY9ksqcrsUGcQR5cgGvYK6KZVJG5fwgCdoxGALRfiX4HhrYbqtYC+6lP7DjW+LA+EVmxzOJyIFollzi9mnfsq7NuQhdme2QhLVQlUgXuCFZ2FeT2dTQg== 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=SBGRfS2nosjhf2Ap5cgALUDykFntsRi6zHaU+lQKCKw=; b=Sotu0ixvkwg5xmXbQVYjkLrIqB6MXq2ip7ed4dJnJJ771drw8GNpm6HO3rgvqjk2VZT8NTA9Kqbmyr/ZmF824sv7i+lJ8mBpHnwHMyuQ7CFqnACpCz36Z9MoxE0cynY46+dZJElRPAv3+5TAyQeolwLSly+T9PROweaWdcpvDS8= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from BL3PR12MB6380.namprd12.prod.outlook.com (2603:10b6:208:3b3::7) by MN0PR12MB5980.namprd12.prod.outlook.com (2603:10b6:208:37f::18) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6521.21; Thu, 22 Jun 2023 16:33:35 +0000 Received: from BL3PR12MB6380.namprd12.prod.outlook.com ([fe80::c39d:ccaa:b3f3:6b38]) by BL3PR12MB6380.namprd12.prod.outlook.com ([fe80::c39d:ccaa:b3f3:6b38%6]) with mapi id 15.20.6521.023; Thu, 22 Jun 2023 16:33:35 +0000 Message-ID: <7c11f087-72ee-eb18-cdcb-774d7848dcef@amd.com> Date: Thu, 22 Jun 2023 11:33:30 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH v6 25/27] cxl/pci: Disable root port interrupts in RCH mode Content-Language: en-US To: Jonathan Cameron Cc: alison.schofield@intel.com, vishal.l.verma@intel.com, ira.weiny@intel.com, bwidawsk@kernel.org, dan.j.williams@intel.com, dave.jiang@intel.com, linux-cxl@vger.kernel.org, rrichter@amd.com, linux-kernel@vger.kernel.org, bhelgaas@google.com References: <20230622035126.4130151-1-terry.bowman@amd.com> <20230622035126.4130151-26-terry.bowman@amd.com> <20230622141255.00006d13@Huawei.com> From: Terry Bowman In-Reply-To: <20230622141255.00006d13@Huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SN7P222CA0009.NAMP222.PROD.OUTLOOK.COM (2603:10b6:806:124::34) To BL3PR12MB6380.namprd12.prod.outlook.com (2603:10b6:208:3b3::7) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL3PR12MB6380:EE_|MN0PR12MB5980:EE_ X-MS-Office365-Filtering-Correlation-Id: a47e0c99-bb0c-4ba6-72bd-08db733e6b1a 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:BL3PR12MB6380.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230028)(4636009)(346002)(376002)(366004)(396003)(39860400002)(136003)(451199021)(6512007)(2906002)(6486002)(6666004)(478600001)(83380400001)(53546011)(6506007)(186003)(4744005)(2616005)(5660300002)(7416002)(36756003)(66476007)(86362001)(38100700002)(4326008)(66946007)(316002)(6916009)(8676002)(31696002)(66556008)(8936002)(41300700001)(31686004)(45980500001)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?UFNhcDNLVWkvYzV0N3loZDYrUGhHR2JNS1pNTndDRjROc2QvR3dJQ0xvWlpx?= =?utf-8?B?NG5HZHlWT0ZpdGVrOXZleXI3QjUwNnpxQU9RQnIrcHkrZ3VBUXZ2UUhQbnhR?= =?utf-8?B?TE41ektqZENNOXNXa1JPY1pML0ZBZU9hZ2laVmpERldScEsvdm43NE1GY3Ft?= =?utf-8?B?OTZpWUk3K1NDS2p1T21zTGltR1dRMkJaNGlHWkZxeHpLem9tODdLYk9udmJW?= =?utf-8?B?T1JBOGYwN2dpQXNOOGVKb2dqNjNGRmMzUStmMTVlRkhXVHppTjZnL21QWmlE?= =?utf-8?B?UVZHWnFqQllrRUVCQmRMKzRwM0lrbWs2QWt2cEE0bTR5YVhWZnhtOThZbEpa?= =?utf-8?B?UmVNRXhxekp6MFhtSFFoMk96YTRtTUtPaDNLSktSR01jaHY3b0pNN2Y0V2ZX?= =?utf-8?B?MkpsSjBuMGY0TWFUN2xvSUdBSEE4dVJOQm9qSmdEZWxVS0ZJMVhpNURVMjNu?= =?utf-8?B?RG9sM0syRVF4NkxKZXdqT0tZeStxcEZMZXJmb0pRRkZIR0M1RDN2VksyQWw3?= =?utf-8?B?d21zbWZFd0E1cEdVNStMUkExZWEwVmhuMWV6RGdLZzQxSkh3NWJza0xPSS9a?= =?utf-8?B?WDgrbXdEMkl0QlJIYzNERUpKUGdOamF4WFV5dVA0Vlp1UzNzcWZCOUNDTmp4?= =?utf-8?B?STBEcWgxYlZYeDA3VEIyTUp3ck1BR1Q2WjFneWYwNEZUek5UeFgxemJQNXBk?= =?utf-8?B?ZzAyWi9vbDFPeVBPTVZjQlg3a2JRVVVyYTNpTlJGMEh3WWl2NkV2U2VwcWNZ?= =?utf-8?B?QVRBQUUxZndNVk5QY092V2dFUlB5QU9RUzVwdkZQL2Zzbk56MVEwMXdINWh3?= =?utf-8?B?RWdNNDFYczh4NnBUMWZUQWFMNnBvQ2JpbStCQ2grTEdncm5rZ2JmZXBhVFRh?= =?utf-8?B?UkorUk96TTE5ek9VTVJ2L2NSTmszVDUrRjBDRzNZSlhSZmNsQitlSlVGc0ZR?= =?utf-8?B?ZXFJK2IwY3kzQktDQXBCSDJUa0NxdHRzVFVXZzBETGJmT2grWCtrY1dWUWh5?= =?utf-8?B?Q0FWSHlvaExUVFBkTmcvQW1uZkxEUENsMzhMVnFkLzNwK29teXVOdkN6S2pI?= =?utf-8?B?Sk90c3VZSFd3NEFSYWNCaXQ0bFhxbldmeURlTHBpZVFNZmVvbVhlVGxMRC9W?= =?utf-8?B?STF3dDNyam1NS0w4anR3cFlwdWsyTCtkL1pqSC9saCthMkhZOWJOckw4dTE5?= =?utf-8?B?alU4SkxWR29Ha1puOUlBZnlvU2U2d3JlNTFYZVRMTUlDSlM3dm1vcUpiVktC?= =?utf-8?B?NVBkTWZ2VHYvU0lXQTYwUkRoeEZ6OUZ4ZVZsYWlHMGUwQWYrTHBTRzRDS283?= =?utf-8?B?Ym9tU2RrUEQxeVpMYnBVcElGZGhWK0RCa0lKaTVWWUxXWnlaeXdEcStrZmhy?= =?utf-8?B?WlhwdGFndmJNb0R4eThtVW9xd2JYaS95NWZuN3JDVSt6Wm41aThWWFFYU0Fh?= =?utf-8?B?cnRPVnhLQnBNcWNTMzkrUlE3R2V0a2NkWTZBR1VkS0VCRXRRS0RZdFJrcHpo?= =?utf-8?B?aWFjMkZ3MjYwbGNEZG42MUIvM05BOXVsd2YrbEI5eUJ6NTZqQkdpcjI1dDJK?= =?utf-8?B?NGUrMUFZNDVBaW9uSlRSRmEwaWpoVytLd2xwVmJldUY1VUtDM0ZaV3ArVUcv?= =?utf-8?B?cWJGbFVWTXBrVTVDMkNySG42QTZPdWF4NDVrV3RMb1cxb01xQi9nL0Y3MytJ?= =?utf-8?B?VHh0WTB3SVdOMlBzOFFhT1ZmdzdLS1JPMWhEQkozKzYyS0hoalo4QXVqdkxq?= =?utf-8?B?TFo4SUV0c0FkakhZMUs5dUtoL0JwZ2pJZGRlbWFRMzUyd0FJRGFPMVd0Njhu?= =?utf-8?B?MXZIWVVzZklLUnMxcEtlamRwd0JOZk5oUUxwa0VNN2N3WHNVUVJuS2lJWkNY?= =?utf-8?B?TktqTVNhd1Y0VmZKK1plbFYvR2ptbXc2dXlJZjlUbHpFVCtOQ3RoVlhGVXlH?= =?utf-8?B?WGJTaHU0U0JTRUFJYkp3Qi9rNVZ6bERPZkpwK1BKRjE4aGZIamlJY3g2NHZv?= =?utf-8?B?N1Y0MG9vb3cxYnlJT1VTWVlkLzlrT29DS0dOa3I5WjY5K0Z1a1c5c0JMMUZq?= =?utf-8?B?SkRwZUF4enZ4OWdjRVNYekNCZjVVQUUrRVQ1UURWUUtscVAxNGtLZW9PTDl2?= =?utf-8?B?eExaMWwxZ1kreGhuMWZqb2cvSXlqcFFSdlZaQ1hlZHY1VlYzUTFqZjFrYnlo?= =?utf-8?Q?PTCmd70VktZaG/D5j0DksCly/IcMBd049dKM4yQXidcN?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: a47e0c99-bb0c-4ba6-72bd-08db733e6b1a X-MS-Exchange-CrossTenant-AuthSource: BL3PR12MB6380.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Jun 2023 16:33:35.6325 (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: yhLfifE8YUxt+wTohXQMk6z/rD1U14pcpoVCScfcP20aWUcXQgIgtzU2LfFJVto3Yog9pwgVPe/kuKslHFT9oA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN0PR12MB5980 Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org Hi Jonathan, On 6/22/23 08:12, Jonathan Cameron wrote: > On Wed, 21 Jun 2023 22:51:24 -0500 > Terry Bowman wrote: > >> The RCH root port contains root command AER registers that should not be >> enabled.[1] Disable these to prevent root port interrupts. > > I'm a little dubious about a 'because the spec says' so argument. > If we can describe the path by which spurious interrupts turn up then > great - if not then fair enough. > This was added to follow the spec. The RCH downstream port contains root port control pci express capability for enabling and disabling root port interrupts. The interrupts are (should be) disabled by default at powerup according to the PCI spec. We know SW does not enable because the RCH downstream port is not enumerated or managed by a port driver. I cant say this patch is absolutely necessary but was not comfortable with removing it either and want to avoid undefined behavior. Regards, Terry