Received: by 2002:a05:6358:3188:b0:123:57c1:9b43 with SMTP id q8csp9601434rwd; Wed, 21 Jun 2023 09:20:39 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ5UFSeqIgIi23dqcJR6CnORW0cIOPZojz2VZHQChJ/WFpXmFVyE3TavyiWYZHaxPbXQroGA X-Received: by 2002:a05:6a00:803:b0:668:81c5:2f8d with SMTP id m3-20020a056a00080300b0066881c52f8dmr10373938pfk.3.1687364438723; Wed, 21 Jun 2023 09:20:38 -0700 (PDT) ARC-Seal: i=2; a=rsa-sha256; t=1687364438; cv=pass; d=google.com; s=arc-20160816; b=pONocwDUbs/68PC2LR71fx4lRscUImqR1x4vVSGbqMc+v6bchcwQMs85QA7Ixealh+ cfCJ/mpHJKp1iY7BDyi2XNp+OY1X3M/kN8XM1bFvUVFW/I+6w1rnYPWT2ZWU9qEq8Fxg 6MtsCz5ZM2q6qQrBkSkuoCDr/bSP49lMdtvJzakwnJuV1uuQ1SV4Ay2UL1YR/xUJDfES bTveDef3rgO3R4kmQjoqyMGuFcNpgNmy9D60INX6igIZmZb5cun7EEkEnMpnPNokEVmL ikeiA/iSpowIp5I7Zd+vD/AMbtf5pcx6niEq8CsMqIp20mWpr6QjeZUeaOgntzhC03ML zxag== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:mime-version:content-transfer-encoding :in-reply-to:from:references:cc:to:content-language:subject :user-agent:date:message-id:dkim-signature; bh=2XuIkuVB09s2z0EXoibkagIFTtxAv4WP2pPDyyxrThI=; b=efa4YCnXMkjEV7zskDLLct/hk35G/2Qf0Jc86ol3SEHbY48N+p4vScAvdiTL5Ujb0O Q973izr8ROOq8NJjgm1rbRz2KDOt9NRYn+o5tLo7gstiyg3PnPdhTKd8uPW9DtKQ8Rmx 8PkFH8JZNOLv+W1tl+pf3vkTYnPuc1J4AMFug0AbGgauoPE/zaMc7N6NkkUhxN6H8ez3 olJOZfrukbh+bQWhlxKJIvYsM+PgnYUoagHodN3jrjYk631WwLYpGRDTL/PqGIpcDnNj NcGWxfmhfpl7+Fe+hpq1gll1fqJywGdkG+Jos09gqhY7liDcMUjbAy9mD9nAoIVBzmY7 vj3A== ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@amd.com header.s=selector1 header.b=wSwpo+F0; arc=pass (i=1 spf=pass spfdomain=amd.com dkim=pass dkdomain=amd.com dmarc=pass fromdomain=amd.com); spf=pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-wireless-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=amd.com Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id s13-20020a63924d000000b0054201a3f08dsi4401762pgn.592.2023.06.21.09.20.29; Wed, 21 Jun 2023 09:20:38 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@amd.com header.s=selector1 header.b=wSwpo+F0; arc=pass (i=1 spf=pass spfdomain=amd.com dkim=pass dkdomain=amd.com dmarc=pass fromdomain=amd.com); spf=pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-wireless-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=amd.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229602AbjFUQPQ (ORCPT + 59 others); Wed, 21 Jun 2023 12:15:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42888 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232666AbjFUQPJ (ORCPT ); Wed, 21 Jun 2023 12:15:09 -0400 Received: from NAM11-DM6-obe.outbound.protection.outlook.com (mail-dm6nam11on2053.outbound.protection.outlook.com [40.107.223.53]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C1BF186; Wed, 21 Jun 2023 09:15:08 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=E1xmLpc+1ef5weZFgu6kVmIkGRPu/NsuOH9Ttd8AAVy5ZFHULy7Ctr2SXqBn0hJhaY8Z9sQiVspGd6duGWDqtEvVvtQOpw2Jiq7RgqfJcrCVzKRGAHGnfJByw3tsm3HHJKx/G4pO47OGegOfHRbUKCGGXH8nxWFXzzNjJy8b7VITEyINiTe1tizQMaNLXfXf1dJcMqB1g+PjZJOhntRSvnjuA51221buVpX8aBZQTCI+IfvBkLiXBvi4rKF8VHCTEElE8cuD9OAcAIYssNRz943Y9ZtkRdQ3CiE8y4Q5OCJZtp7xBWwxCxmFDnRDHk/B0wS4aHK14MBJ11FEN4lYmA== 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=2XuIkuVB09s2z0EXoibkagIFTtxAv4WP2pPDyyxrThI=; b=WoRnwhqT2Esd8RNktcLsIpNARcs/Jm23ypTAMlfqGRJ5pmKK+cna8MzCm+muOYQ/NqYPvdg0x2J40mc+eJKR6fqc2MiT+B2z2e26BtKpOIGq9DwGGgqL+fS/SnYlWUZl4gRUgd5mBrgfGgICw7rrFpuvov2zkoq8RUWQ3+z4QPLnl79LEMZ6qBV4XPjP1V04Q0Ep3/d9ZxYcpypwKpEDWq9Nr7rHUEkvwvE09p7iJnr//MjS5GyhM+EZh10qW3OqTX32UfVb9CN36zBPZUjENXwHVXStDok93l0EFsDNfbPC0+ZF25P7JnvmeZ8RqSWY9z1bphjtdOCI3W78YCZj4A== 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=2XuIkuVB09s2z0EXoibkagIFTtxAv4WP2pPDyyxrThI=; b=wSwpo+F0gqG87cDBUm4gI5LwnqC2UYoCbiq+XapIEpYXslzegdcBThn/OVeYMXEBBSiv9VgrmNEArJgC9CYgfRqjUk/TzQDU4nOX/+of/y/YVdvTCiHA8C+cPhL4HjcoF1GEADgAkochIqP7WBBViPxhauRl30PSq9OaNhaU6jU= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from MN0PR12MB6101.namprd12.prod.outlook.com (2603:10b6:208:3cb::10) by MW4PR12MB5602.namprd12.prod.outlook.com (2603:10b6:303:169::20) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6521.23; Wed, 21 Jun 2023 16:15:05 +0000 Received: from MN0PR12MB6101.namprd12.prod.outlook.com ([fe80::dfcf:f53c:c778:6f70]) by MN0PR12MB6101.namprd12.prod.outlook.com ([fe80::dfcf:f53c:c778:6f70%5]) with mapi id 15.20.6521.020; Wed, 21 Jun 2023 16:15:05 +0000 Message-ID: Date: Wed, 21 Jun 2023 11:15:00 -0500 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.11.2 Subject: Re: [PATCH V4 1/8] drivers/acpi: Add support for Wifi band RF mitigations Content-Language: en-US To: Johannes Berg , Andrew Lunn , Evan Quan Cc: rafael@kernel.org, lenb@kernel.org, alexander.deucher@amd.com, christian.koenig@amd.com, Xinhui.Pan@amd.com, airlied@gmail.com, daniel@ffwll.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, mdaenzer@redhat.com, maarten.lankhorst@linux.intel.com, tzimmermann@suse.de, hdegoede@redhat.com, jingyuwang_vip@163.com, lijo.lazar@amd.com, jim.cromie@gmail.com, bellosilicio@gmail.com, andrealmeid@igalia.com, trix@redhat.com, jsg@jsg.id.au, arnd@arndb.de, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org References: <20230621054603.1262299-1-evan.quan@amd.com> <20230621054603.1262299-2-evan.quan@amd.com> <3a7c8ffa-de43-4795-ae76-5cd9b00c52b5@lunn.ch> <216f3c5aa1299100a0009ddf4e95b019855a32be.camel@sipsolutions.net> From: "Limonciello, Mario" In-Reply-To: <216f3c5aa1299100a0009ddf4e95b019855a32be.camel@sipsolutions.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: SA0PR11CA0193.namprd11.prod.outlook.com (2603:10b6:806:1bc::18) To MN0PR12MB6101.namprd12.prod.outlook.com (2603:10b6:208:3cb::10) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MN0PR12MB6101:EE_|MW4PR12MB5602:EE_ X-MS-Office365-Filtering-Correlation-Id: 8c70935e-48eb-4e8f-026f-08db7272ac8d 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:MN0PR12MB6101.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230028)(4636009)(366004)(346002)(136003)(39860400002)(396003)(376002)(451199021)(38100700002)(5660300002)(53546011)(26005)(6512007)(6506007)(83380400001)(186003)(2616005)(7416002)(41300700001)(2906002)(8676002)(8936002)(36756003)(6666004)(478600001)(6486002)(4326008)(6636002)(66476007)(66556008)(66946007)(316002)(31696002)(86362001)(110136005)(31686004)(45980500001)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?Y2plNGpaeUxlRmNrOGFVcFVKYWNoeWJyZHJGay83eVYxNXNQaFV0aVRhd05K?= =?utf-8?B?ak9jY2preXg4Vm9UMVUxSWVtUkdtbFV2d29DVm01cTlJZnVoREdWY3pjSUVT?= =?utf-8?B?c0Z4dmRacnkyQnIzcHVLc2I5K1V1US8xb1NXK3czZUxtSUx3bk55eStadmN5?= =?utf-8?B?Nnlub3NlK1NDTkp0L1o5cHIyU3lvQUFHU1Q5dEEyeWFxNXJ5ZnMwbDBtUjFh?= =?utf-8?B?Z1Y3UUNwRU1FUnRFYWtZdWJHVTZjVHlsQURydG5GQjgreCtobS8xMmpBd2Rw?= =?utf-8?B?KzRJNjF5d1hvZDJjWVpRTnVqRnN6VFJ2SThXNmhHaHJwL1J5elBwRktnTDhN?= =?utf-8?B?KytjK0s2QnA1bGQ4MjNIaytYdTZuUHB5MjQvL3QxbmtPSldRbFhnRW5sdzN5?= =?utf-8?B?VDJmU284NHh5SGVCdEdGTVd4MDdFZDF5L2d4UWx5eldXVmRLd2p1QWZnNWUr?= =?utf-8?B?dXJ1OWpMRWc4OW5TTkxRQ04zc01XVzhkOWRHaWJHdzJacTB1WVBYeXp5Qkxa?= =?utf-8?B?NTZuUlR0b0tjNzkzY1lIMWUrMU12MzNrcVcvSDRLcGg5RTJyVFRRUjBNNkY1?= =?utf-8?B?MXlkL3NpMURzWERHUjJIZkViazQzTlRCZ01wRnE4NCs5d2ZsdUFiUEhjWlZm?= =?utf-8?B?ZUxXdmZvYnZ6K2xjVmVQYjZENGdLdFFmQWwyVjdjZzcybzZSOW1kV0Q2Z0Rt?= =?utf-8?B?eDRqcmlPbUNibCtlVU1OVUtDa1RaTDFZTFdhYklQamw0dWVXWWxHbDZtWisz?= =?utf-8?B?c2pHOTFFT1E5YmdtdHZKbTRkclJpQUhiblEyL2hYWTd4cEhiWTJWYjlaQW1Y?= =?utf-8?B?NUJEV1ArMnBIQ0QrWG5yV0o3aTNHS3AyL25GMThrMVR5UE9nN2tGcEEwM3Vo?= =?utf-8?B?SXl0MHYxZldCWFdBR1RSbTFoZWc0dEdidXU2dy9JSGNXUWcrSEZDZ21XRCtt?= =?utf-8?B?bDJCN2RnNnYzc21MMk8wN05ZUnZoU0JCempLTWVpZThjZlRxRmthaXl2MG9F?= =?utf-8?B?YWtSUExlUDlLVG5pOW8vZVRLTExjbXhhOGZEekV6UytZczlmeXAvU2o3YnYr?= =?utf-8?B?aS9JTjRrT2xJT2VVRUhFdmgya0EzMGJoeVdtdlNVSVZjalFGS25zZUp5bmhh?= =?utf-8?B?bW1xUGQvZ3BpaFVVWk55eVVzNkVRcktBTzhuVGdNSnUyZWFkYjkyVTR2YUJG?= =?utf-8?B?MGhuZzNLTjlFUmpJQlU5bkc2UG1lT0tScVArRGE3N2gwSjFwMjcwVXNwRk5D?= =?utf-8?B?R21XT0JsWG9sQkJ2T2xxUWh1cTAya2RDejVjbzFGL21EREpiamd0bzZ4OU5D?= =?utf-8?B?andyNmNTeEw5cTQvQkRuZ0t2ZTc3STVLS0xxc1pnZnFnRHhOL2lsN29BWllZ?= =?utf-8?B?QjBHQ0NCcWpLVUp0WGpPOTE0LzdDdi9DZk05WFZmUUpIN1JNS3ZjOU9CeWJm?= =?utf-8?B?ZXVOM2g2YXJtK3ZweWdFYlQwY1NvUWtnS1BQZm5yREttcnU1c2VPSWo5T0Np?= =?utf-8?B?bEhWK0hocGlSdEtJbTJUdGs3M2dqRGN2VTg1aTMyd0Z5UEVRNHpwUkFvRzls?= =?utf-8?B?NGNBRmJYUS9iM1Y5THlia0pKKzZqclEyUU5aNTRBOFl6dmthWnR3emxZSTcy?= =?utf-8?B?THg4ZzhYSms3MFp1dExCWEJRZGdlbU1vZXV0Y2U0SFEzV1pQaE92L2U3cU8z?= =?utf-8?B?WHJyUHU5UzFPNjVEcmNkeTFrZ05pRFVYNVlvWGo0MnR3KzRiZk1XVXNicWVB?= =?utf-8?B?UnRleEZNdDE1TnU2dy8xSXZQTmxFU0RyRTRXc2NzTFBXYkNjbFMyT0crU1Vp?= =?utf-8?B?RVpwV1NROXJUcXpMaVdGaTN4eWNPb3J0MHpRSHVsZWhHTDhPRUZMOU9FeGVD?= =?utf-8?B?dEhLWSsrTXh0U1JPMnZkY3VscmZrRzY3MmFqMnMyc1ZWaVRCT2tNOHRIVzBp?= =?utf-8?B?cHFLT3ArTi9IMUhHTGpUY0hnajBZc3VGMEZvbWtiY3p6WkFWT2Jla1RpSERZ?= =?utf-8?B?MG1QMDJpSk9sbkxPNG83S21RQk1neStFZTNnY014TlhBWjQzVzQrSFNuVWhH?= =?utf-8?B?cDNyNUhOOVZHTzJBV0ZsN3loL2MzTmNUNUhMWDBBU0h4T0w5VlJNSytrTnJr?= =?utf-8?Q?3k+8C/2FQKzWb5hwJlMrWKC/q?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 8c70935e-48eb-4e8f-026f-08db7272ac8d X-MS-Exchange-CrossTenant-AuthSource: MN0PR12MB6101.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Jun 2023 16:15:05.1658 (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: aCcOnNKscodZcJZ3WJUzqWYGQI1IEtArbgmYSfl+Uf0qqlHf1iyRsMTcNs4PSfXqWv6fCVGaH9RcZhE4WeZbDA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR12MB5602 X-Spam-Status: No, score=-1.2 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FORGED_SPF_HELO,NICE_REPLY_A, RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_NONE, T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org On 6/21/2023 10:39 AM, Johannes Berg wrote: > On Wed, 2023-06-21 at 17:36 +0200, Andrew Lunn wrote: >> On Wed, Jun 21, 2023 at 01:45:56PM +0800, Evan Quan wrote: >>> From: Mario Limonciello >>> >>> Due to electrical and mechanical constraints in certain platform designs >>> there may be likely interference of relatively high-powered harmonics of >>> the (G-)DDR memory clocks with local radio module frequency bands used >>> by Wifi 6/6e/7. >>> >>> To mitigate this, AMD has introduced an ACPI based mechanism that >>> devices can use to notify active use of particular frequencies so >>> that devices can make relative internal adjustments as necessary >>> to avoid this resonance. >> Do only ACPI based systems have: >> >> interference of relatively high-powered harmonics of the (G-)DDR >> memory clocks with local radio module frequency bands used by >> Wifi 6/6e/7." >> >> Could Device Tree based systems not experience this problem? > They could, of course, but they'd need some other driver to change > _something_ in the system? I don't even know what this is doing > precisely under the hood in the ACPI BIOS, perhaps it adjusts the DDR > memory clock frequency in response to WiFi using a frequency that will > cause interference with harmonics. The way that WBRF has been architected, it's intended to be able to scale to any type of device pair that has harmonic issues. In the first use (Wifi 6e + specific AMD dGPUs) that matches this series BIOS has the following purposes: 1) The existence of _DSM indicates that the system may not have adequate shielding and should be using these mitigations. 2) Notification mechanism of frequency use. For the first problematic devices we *could* have done notifications entirely in native Linux kernel code with notifier chains. However that still means you need a hint from the platform that the functionality is needed like a _DSD bit. It's also done this way so that AML could do some of the notifications directly to applicable devices in the future without needing "consumer" driver participation. >>> +/** >>> + * APIs needed by drivers/subsystems for contributing frequencies: >>> + * During probe, check `wbrf_supported_producer` to see if WBRF is supported. >>> + * If adding frequencies, then call `wbrf_add_exclusion` with the >>> + * start and end points specified for the frequency ranges added. >>> + * If removing frequencies, then call `wbrf_remove_exclusion` with >>> + * start and end points specified for the frequency ranges added. >>> + */ >>> +bool wbrf_supported_producer(struct acpi_device *adev); >>> +int wbrf_add_exclusion(struct acpi_device *adev, >>> + struct wbrf_ranges_in *in); >>> +int wbrf_remove_exclusion(struct acpi_device *adev, >>> + struct wbrf_ranges_in *in); >> Could struct device be used here, to make the API agnostic to where >> the information is coming from? That would then allow somebody in the >> future to implement a device tree based information provider. > That does make sense, and it wouldn't even be that much harder if we > assume in a given platform there's only one provider - but once you go > beyond that these would need to call function pointers I guess? Though > that could be left for "future improvement" too. > > johannes There's more to it than just sending in the frequency that is added or removed.  The notification path comes from ACPI as well. This first implementation only has one provider and consumer but yes, we envision that there could be multiple of each party and that AML may be the mechanism for some consumers to react.