From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from OS8PR02CU002.outbound.protection.outlook.com (mail-japanwestazon11022138.outbound.protection.outlook.com [40.107.75.138]) (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 62F1F13EFE3; Tue, 30 Sep 2025 02:05:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.75.138 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759197932; cv=fail; b=CazLOChsp9TNV8Ll9yPl0ktW9jzRG7szJrIW+rBi7lzQRU2yQOUo3fZ+0FyhWjiIZbBZzm7P9SPxr7gCpjRR/u94O2S858ooUzKqewletqkB3A/9XmfDqeOfOwKuYjFW9qAGATkkiym3FchnLWcHCMqg3SE9pFHBDM6SQlThgFg= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759197932; c=relaxed/simple; bh=2sQ7yDUt1dzDRCXlKCvdePA6iplsu/nnUL5y9kuFK6M=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=dHwtYOgB79sNFHPCHShQo0LuJnheW/D+18kB32GsgKhikwdJhN9VfPrC2mR2oYQQspT7e7Rw/RkaVBBpaSzWKjBu4QXXAwq1eEkDQzmTNZOTFoXplvabBq1r2Qzv4+yGQDHIqWTUkvzE+dOFkX4omkw/Vtcl8Jkokp1Lv9W7SOU= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amlogic.com; spf=pass smtp.mailfrom=amlogic.com; dkim=pass (2048-bit key) header.d=amlogic.com header.i=@amlogic.com header.b=WsBC8zPK; arc=fail smtp.client-ip=40.107.75.138 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amlogic.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amlogic.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=amlogic.com header.i=@amlogic.com header.b="WsBC8zPK" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=MjmtgmBCVF/rtjkzh7vPX+HhM7Q3X9X/BSHeHlCbUcNnKhsKNBt7AUTtCnVkWHmCgL1DRjMwh8DykZ+S1qiq/P0sFosGYZSNSzuquasOH9zZwYKqwkUu7fipMKTwhUQEhETr9lfd8sFNnt4NEjFvCKDV+29vP55cbIVKDo2uQ0w7Ie+9XMzRQpWCkE63fTvw+tHRDd/DsQoNN1gXkMO0Y1aSWgDbMTJz3d66j+soMhGK/6KMswn9HShkNQp6arfv9l5yZdw7rP5B8ZQwAa+J0LuRcI1MrRWCMkh3QLmc6AZB9oISJhTEvM5u+p9TA8XRlxSCh6PX576W5bbxdzY0xA== 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=71JOEv/Db94sl02aDS2Ms3EvhNizH/iYcFxKQSOQwp0=; b=YHsKT3g9l4snF7HvgcTVg27yeLga879nBCl0FNbwNTglm40Ea5FmOXn9YN7mIdDfMvjEM5U8JU5oGCUY66coTDsF5nX+V/HfHT0YCjsb3SWNkC6RiHYIHQn3H5wHslYQ5EquK3rIRkZUMM+FNITRGmRDUzIY9TA6YtaeZE3+0J6iUIRelSZ0MglwKYwDVsMqmjvC62GmfkRcweUOcGekQLWfLz0fUQ2qXGW6ViLuenuo/92x2hs2TyLfxJYUFxm6WNLlw4edA+t/wXSVlnQB3UCgzDxO3RlHPuYpaZefk3CGlsbOTI4KRjdromW1ioW4VJibzW3ZP6nZVJ3VVBsBiA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amlogic.com; dmarc=pass action=none header.from=amlogic.com; dkim=pass header.d=amlogic.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amlogic.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=71JOEv/Db94sl02aDS2Ms3EvhNizH/iYcFxKQSOQwp0=; b=WsBC8zPKfAKEY6knntKanfw0EAZFS8gk/gLPXI/8dFdcvJU+3B2/RQbuFBoAaNAFnb6G28ZqnjnlWEtfZxfXi7UHOiuxDTwwEHicGkp8GjGlEnMfjnzMDcuGB5q2X4BPjjZULnAHBjoFkozQQYxCABvr/gmJVlBp1nFv9BAjf2y7PuVIUZK23YCWhsECr+b6Xzkfwf2Yk1V+IBPAqYeg+YuY89hZCQSFlW+R0tldE83qPvvDVzoyew8/PtB287RoXGjHGL4SdT2cnN5JizpG/fpzox17mkvErNK+hckS2feSU2xh/BLUhOS978JH0lV37qzRWjUFkZnP3pghr5d5uw== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amlogic.com; Received: from KL1PR03MB5778.apcprd03.prod.outlook.com (2603:1096:820:6d::13) by SEYPR03MB8741.apcprd03.prod.outlook.com (2603:1096:101:20e::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9160.14; Tue, 30 Sep 2025 02:05:23 +0000 Received: from KL1PR03MB5778.apcprd03.prod.outlook.com ([fe80::e1e:5c95:a889:828e]) by KL1PR03MB5778.apcprd03.prod.outlook.com ([fe80::e1e:5c95:a889:828e%5]) with mapi id 15.20.9160.015; Tue, 30 Sep 2025 02:05:22 +0000 Message-ID: <1639bb9d-9cb7-409f-bbf8-bfe4a5d1b8bc@amlogic.com> Date: Tue, 30 Sep 2025 10:04:49 +0800 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] clk: meson: Fix glitch free mux related issues To: Jerome Brunet Cc: Martin Blumenstingl , Michael Turquette , Stephen Boyd , Neil Armstrong , Kevin Hilman , linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, linux-amlogic@lists.infradead.org, linux-arm-kernel@lists.infradead.org References: <20240929-fix_glitch_free-v1-0-22f9c36b7edf@amlogic.com> <20240929-fix_glitch_free-v1-2-22f9c36b7edf@amlogic.com> <20178015-4075-40e9-bbf4-20ae558c2bef@amlogic.com> <1jldyzrv2t.fsf@starbuckisacylon.baylibre.com> <9834c7c5-9334-4c78-a2fe-588ff03cf935@amlogic.com> <1jfrc563wa.fsf@starbuckisacylon.baylibre.com> <36cd6282-ae1d-43f3-8738-592f043d0ba6@amlogic.com> <1j1pnp5sg7.fsf@starbuckisacylon.baylibre.com> From: Chuan Liu In-Reply-To: <1j1pnp5sg7.fsf@starbuckisacylon.baylibre.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: SG2PR06CA0214.apcprd06.prod.outlook.com (2603:1096:4:68::22) To KL1PR03MB5778.apcprd03.prod.outlook.com (2603:1096:820:6d::13) Precedence: bulk X-Mailing-List: linux-clk@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: KL1PR03MB5778:EE_|SEYPR03MB8741:EE_ X-MS-Office365-Filtering-Correlation-Id: b2951d75-3e25-48bc-e9f3-08ddffc5d04b X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|1800799024|366016; X-Microsoft-Antispam-Message-Info: =?utf-8?B?NVFDQ1hQWlJYaGVITWVuZUxSTW9ISTM0MGxWM0dlNEhjci9FcnNTZm5sTW5x?= =?utf-8?B?bUR4alNjV0FLbDVHODhDbWwycVA0TWdEUTEzV1BGVmhSQXNqc2ZmTGdvbTRu?= =?utf-8?B?eVV5RmJZenQyZlhNUlkvTHZzUXdvZlZmZzlDREIzbmVuZUxOek1sRmZFM3hl?= =?utf-8?B?ME5QblJONVlnYjhjbWwwYlV6cFhjSDJhNmRaLzhxTHR3U25PNVZVVHpWSWI1?= =?utf-8?B?S25KYnl3N0tVZHJVRWFnMkw0akhUVlc2ZmRrTlkvMnRXS2dHVnFjSklENXdC?= =?utf-8?B?ZndlYjFwWDhvM1lVQkQxckFBc1V1NVhtM1BkUzdYU2xKNi9ZRlJvMDdHTDUx?= =?utf-8?B?OFpaeTFCQUdkQWRObjBLbzRydXM0THpaMTNHQ3M0bG9wT2lLdmRBTFk2MjNp?= =?utf-8?B?R01SYlVZMlB5aWFmYzNEeDk1YmtRMFU1eUV5YVFrc0lRdCs0N0U4dStWWXRZ?= =?utf-8?B?YnpJeCsyNU5tSi9IUVNCOTRpSG82bGwzVEcyM1d0VlVtVmdacWExelh5NHg3?= =?utf-8?B?RmdkR3E1QTJhOWswcXZZUVJUVmJGYUZBTFU5U1VPWTFNRVV3L3RRSVcrS2V0?= =?utf-8?B?ZDRUVXBwV2UrL1BSdDRrK0hXRER6Wk91SlBmRVRjWDBqLzBlekhlN2dRdkJJ?= =?utf-8?B?RVJ4Vkp2Vkd6Qk9uanEwRER5RzRnOXVGY0NKVmhncGV0bW5JYWdKK2hIcnRo?= =?utf-8?B?WmZKa1dRZXpwQUp0bE9pbGFhM1pKYlYvaDdvWThqdCsvdCtLUEhFTjZTTTRG?= =?utf-8?B?ZFZ5cmRYQTRNQkhoUCtTSzdJOGFrSk5hekxRZG4wOTJhcjR1dkIwVkR6VWpm?= =?utf-8?B?cEgrcDRpbWorMm1haXlrYVp1SVVzUit5VlZOMWRiTnBEa3lBOFF5Tkd4cWE2?= =?utf-8?B?b3pIbGtaays5Q2FTaFJCQjJweGlWSFVodWpPZEpTOUNVb0RZODlFVHVHUVQw?= =?utf-8?B?VXNzbFlocDMxYVJjZitXMjMxdzAzbVRzRnRidC9YVGI5WGpmL1hCUGdoN3BF?= =?utf-8?B?OTNVbUorWWFOZmY3UFRBR0JqbEtnU000Z3pNckJ1cmVJdG5HQ01aK1BEeE5W?= =?utf-8?B?RzEwNDBkUmQwRHBLdWNxRVdsL0g2R2psT2UxWmxlTTgyWTZYUXJQRm9hYnBr?= =?utf-8?B?bUxlSzBWUldlM1Z6eVVtd0R1MXZkYzNSRE5YblNmaDJPZlpHamRONno1cWcz?= =?utf-8?B?bTc5SU0vaUVoZ2hhNDRDL1dWZEw1YWJUM2lvY2RMWk1sUWtXMTBVeHFncUJ4?= =?utf-8?B?SkplSVhTQUdERCtRV2NyK3VOK21FeENkYWh0SjVJWUJSR2VCT0xnRWY5ZU9x?= =?utf-8?B?MGJRZWlnOGVEVU10ZkdkeVRUTUZpYjhwQjFaV21BbGpTTDFyZkw3TVJBWTRr?= =?utf-8?B?SGdHZFptcUJGVUNNeDJjQWVJdGNRemUxSFBQS3orQW5LajVremRVUndIbmFz?= =?utf-8?B?aVZRMDVNQmZHaDA4cHY4TlhtK2xTVWlwVFk2MEpSVDh5WkFXenhTL2FQb3ov?= =?utf-8?B?VGxBeVpDeHBIK1VqVFdPQ01MVHlHNmREMkx6NVQvKzg3UUp5ZU5GN2RTdDZa?= =?utf-8?B?ZmxTa091S0I1M09Da1drc1Y3R2ZTYldVbm1FQ2VDbVVpSitRYm1jT3ZMaVpH?= =?utf-8?B?WmhCamN6Y05HL2hyS2c2TmhGM0wxNHA2YWh4cTNOV1MzR3hObWQxL2Vqd25O?= =?utf-8?B?NjJiWjFSaWVPLzU5dDVwM1ByWjlKdytKeFB0RFFEZXB5UWJCY0JNd09xUWtL?= =?utf-8?B?K1JWcVRYeGdGU01xYm9aejZLT1dIeDViQ0lhQWl3bmR0VzVPcnI5dnV3bmFv?= =?utf-8?B?dDFKeU91OHd4b3FpMkZwL3lwOHJSekRQcmd0OVhMdlhYVS93RU03QVY1bXA4?= =?utf-8?B?cEE4ZXRDKzB1NmYrajlVRGhLaEo3VDc1RTRPWmpqcWNjaTFWSXRobHdUa0NN?= =?utf-8?Q?Lq6BASgesqfT4vIrMSDQTAXgmC7NQGyt?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:KL1PR03MB5778.apcprd03.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(1800799024)(366016);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?SVNnV2g3dmhJYjlaLytUWnc0Wk16NFN0OUF3YlFsbFNrMHZzNFM4anR1dmRE?= =?utf-8?B?V2FMcjJMMms1NlNMeU4zUjEwWnhmMCt0eW9JWmlyWTA1Nlk0TkY4OUdjMnRJ?= =?utf-8?B?bmUvZGhDTDZCK3hCakRvTmpSQWQ4Z2QrUFNVOW9IQWZwRnJQbkZGOCtiUkoy?= =?utf-8?B?SEtpdGRzU3luQU9BWFU0Qzk3RmdESGRhRFBFZWNicXcwcTd3YUFsTFd1NE0w?= =?utf-8?B?dVFTdG93Rm5QS0liaWxvZGhzZ2gzbnBXa2Y1bytLS1BKMkRpQjUyclVHM1F6?= =?utf-8?B?LzNScXFYcDAyQTl5TGRtcXR0UzN2eTgrcGRoUTVkU0Zjb1FCYkJOQVkyNTlF?= =?utf-8?B?TkNWcEFtVnMzUVVpekFYZkd1WHBIVEpUQ0dEOVpEZkxTRVVFTGpmZGdUVkE2?= =?utf-8?B?ZXNJc05STE5vaXJQTjFOeFIrcE5CbHh5TnhaRHdCUmwySXMxRWN2NFFVeGxp?= =?utf-8?B?OVRTeWorZ1cvWUdrd2FSZSt3YkZEZUgvcUtWcmcycERWV2h0UmpUUkxVZGRo?= =?utf-8?B?amdGSUs1dTFTWmt6T2ZTaHlkTXFJL1BaWnRJbXZ5SzVHT0FrSTNsVjdJcENU?= =?utf-8?B?dVJrbE9NMk4zY0dDUDBKcmNQYlhhZ1dQQnM2VWU1SjFPNk1qaWhsVlRtbDd1?= =?utf-8?B?Zk1QWEZQQmc1UU53RnZ5NDUwbENPcHgzSVVGVlB3Mmd5bXE5SzBsZlZQNG5W?= =?utf-8?B?c1hBbmNkUjRneU1HOTM4cjc0MWxYNTQ4bDFEUXU5NmcvSVYzRVJjazQ2NXpt?= =?utf-8?B?MHY0OElXTUJxWUxPQ2d4cjNiTFpzaklTcS9EcVhKRnVSVFVkVlZlVXBpZHZO?= =?utf-8?B?cUF1RGhnY01ERlNGaUNoWVM5ZWhncnI5OUVnSThnYmdYU0U5TmhEMFpjUTI2?= =?utf-8?B?ZmZVVTY3MHB1Qnhjc1FuZ21JZ1NWTys5WStHMi9hdjArSmpzZWR3Mm5UNStM?= =?utf-8?B?VEQvY1g1cnRHNHV4NDk5N3ErdmdPWTlPYzJtZmoyNnNVQWdxektLS3RSR1NO?= =?utf-8?B?NFhmSi9uVGRXT3VFK3Zya1RJdG9nL1dVUDRzbkk5QUJLbEs4SDRoTDlxQUJa?= =?utf-8?B?OWVaZ09HMldEU2N0dVNWZ2FDejVpNnNpWld5T2RDeFJqTlIza2pPdE9XcDBk?= =?utf-8?B?UFVaRFhqUjZocjdEYTFFYUZVcmJFZnJ5L20xZXVVZE0xTHpZZ01KRGswT1da?= =?utf-8?B?OXRzNUhMZHZOSm9YYzR0OGc1c2ltdTlqVXdqMzFIMURxZHc1Rzl4K2RFcm5Y?= =?utf-8?B?SnhjSXk1SmtMMDdoK1czY1h3QVpITEZsTmRwT3drRGlCZ2dvYldwN3gxWHR6?= =?utf-8?B?RTRnejA3M0x0OG9TbWlTWXhCZ3hZekdhKzRjMmZkUlQvQjEzbFZNclhmNENL?= =?utf-8?B?czJaemhuMVBVZnEvckNpSzl2TWtEWk1BbjNMSGNUZTBaSlQ0OVNpWlVORUlk?= =?utf-8?B?ellyaFQyZ2tPL1crODJ2V1V3S3R6VWtteWFVdVlOUXdLQkZQTUxNSHplK1dh?= =?utf-8?B?TjBmS2lXTFpMREJTeVJpSDhVbm9WdDJRMUpXWW1YSFJEbSsyVlVNcE1HcTdu?= =?utf-8?B?eDEvRTdwZ1AyZjBuY0k5enlGK2E2cEJxM1ExdjJTM3k2QkZzTVFwWFlOd3Zn?= =?utf-8?B?dU50cTJidUsrUEtKalR3cHBHRHFIWENyU3BVSUdMUmltbkhYMWFRNno2UzhI?= =?utf-8?B?ZTNYUVAvUmx3Skx5Mlpwa21VV3oxQUVjT3FlOGtvVXhqdU1hZXI2MDRHS0pT?= =?utf-8?B?M2lHOHRVVTNJK21HQ0pRUmJ1WUcyZjJJLzdzMzBYZ0N0ZFAxM1o4RXZCdnRF?= =?utf-8?B?Y2hEZ3N2Y096QlJsWEVUdVQyNENKZHJoTk1ESEEvdHo2RHJ2YzJOUDJHcmxW?= =?utf-8?B?QzZXS1diK0tzenhUdzhZelRDTzFicW9oWFFjV1IzTk9HaW1iWDE3Q09DMk4w?= =?utf-8?B?bEFyRm16UnVhcklrUTJSWGZQSHlnOGtnMjhtK3RMcTJYdGorbFNVU3p6WFlq?= =?utf-8?B?UlBlNzBkK0xCc04xajJtYXNkTHBsM01Da2xvWTAwMXdGSzZZd3V1VFVpQjFx?= =?utf-8?B?a0Z6eUk5MytSWndCMHhuZkN3UmRvMGlLS1g2VzZaazFIYVRZOGs3VFdOK1N4?= =?utf-8?Q?2fV2vF+mNU5vWY1Y3BxYua6Ll?= X-OriginatorOrg: amlogic.com X-MS-Exchange-CrossTenant-Network-Message-Id: b2951d75-3e25-48bc-e9f3-08ddffc5d04b X-MS-Exchange-CrossTenant-AuthSource: KL1PR03MB5778.apcprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Sep 2025 02:05:22.6618 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 0df2add9-25ca-4b3a-acb4-c99ddf0b1114 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: faLErKVuaasSrWW5qnoAcGClOi6shPLMsjSQrwscgy+twaULaxJnDV2Hxz9xlFYsnYUqMa+4CeqOo1C6ZEHQ9w== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SEYPR03MB8741 Hi Jerome, On 9/29/2025 8:55 PM, Jerome Brunet wrote: > [ EXTERNAL EMAIL ] > > On Mon 29 Sep 2025 at 17:31, Chuan Liu wrote: > >> On 9/29/2025 4:48 PM, Jerome Brunet wrote: >>> [ EXTERNAL EMAIL ] >>> >>> On Sun 28 Sep 2025 at 22:55, Martin Blumenstingl >>> wrote: >>> >>>> Hello, >>>> >>>> On Sun, Sep 28, 2025 at 8:41 AM Chuan Liu wrote: >>>>> On 9/28/2025 2:05 PM, Chuan Liu wrote: >>>>>> Hi Jerome & Martin: >>>>>> >>>>>> Sorry for the imprecise description of the glitch-free mux earlier. >>>>>> >>>>>> Recently, while troubleshooting a CPU hang issue caused by glitches, >>>>>> I realized there was a discrepancy from our previous understanding, >>>>>> so I'd like to clarify it here. >>>> [...] >>>>> An example of the clock waveform is shown below: >>>>> >>>>> >>> 1 2 >>> v v >>>>> __ __ __ __ __ __ __ __ >>>>> ori: ↑ |__↑ |__↑ |__↑ |__↑ |__↑ |__↑ |__↑ |__↑ >>>>> ^ >>>>> 1 * cycle original channel. >>>>> _ _ _ _ _ _ _ _ _ _ _ _ >>>>> new: ↑ |_↑ |_↑ |_↑ |_↑ |_↑ |_↑ |_↑ |_↑ |_↑ |_↑ |_↑ |_↑ >>>>> ^ >>>>> 5 * cycles new channel. >>>>> __ __ _ _ _ _ >>>>> out: ↑ |__↑ |______________________↑ |_↑ |_↑ |_↑ |_↑ >>>>> ^ ^ >>>>> start switching mux. switch to new channel. >>> Ok ... but when is it safe to disable the "ori" clock ? >>> Can you do it at '1' already ? or do you have to wait for '2' ? >> >> It should wait for "2", because there is a state machine in the >> glitch-free mux, this state machine is driven by the working clock >> provided by its channel 0. > Then I don't think the 2 flags are enough to make it safe > > Nothing guarantees that CCF will wait for those 5 cycles to turn off > the clock noted 'ori' above. > > I think you need new specific ops for this mux > > Something that would > * protect both parents before changing the mux > * do the actual change > * wait for it to settle > * remove the protection Got it, thanks for your suggestion. I will try to address it in this way moving forward, but it may take some time, as I'm currently working on the bring-up of a new SoC. By the way, On the new SoC, we have standardized the clock tree and PLL design at the chip level. As a result, future drivers won't need to include a large amount of redundant register bit definitions. This should also help improve the generality, memory footprint, and performance of our drivers. >> >>>> Thank you for the detailed report! >>>> This is indeed problematic behavior. I guess the result is somewhat >>>> random: depending on load (power draw), silicon lottery (quality), >>>> temperature, voltage supply, ... - one may or may not see crashes >>>> caused by this. >>>> >>>> Based on the previous discussion on this topic, my suggestion is to >>>> split the original patch: >>>> - one to add CLK_SET_RATE_GATE where needed (I think the meson8b.c >>>> driver already has this where needed) to actually enable the >>>> glitch-free mux behavior >>>> - another one with the CLK_OPS_PARENT_ENABLE change (meson8b.c would >>>> also need to be updated) to prevent the glitch-free mux from >>>> temporarily outputting an electrical low signal. Jerome also asked to >>>> document the behavior so we don't forget why we set this flag >>> Yes please split the changes and visit all the controllers shipping this >>> type of muxes. >>> >>>> Both patches should get the proper "Fixes" tags. >>> ... and proper fixes tag maybe different depending on the controller so >>> there might more that just 2 changes. >>> >>>> I think it would also be great if you could include the waveform >>>> example in at least the commit message as it helps understand the >>>> problem. >>>> >>>> Let's also give Jerome some time to comment before you send patches. >>>> >>>> >>>> Best regards, >>>> Martin >>> -- >>> Jerome > -- > Jerome