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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C4009CAC5A5 for ; Wed, 24 Sep 2025 20:59:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:MIME-Version:In-Reply-To: Content-Type:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=qLQwVc1w/sS3cRfltjv8ih4BvpnDmQnaS6OQNsdhaKA=; b=KgGdugEpeecZmIjf8U7OWXz21K QCMUPkSU6cUdmH2I9iBaP+OFiGfEQ6SOuqyXIbYNvw5tORn1JxBnNd8TgEYEXutCIPzM8XLdbLFus vDleVf3pAZqIdBZPHOKMtK/1O8jCiX27DCTvUbTnELN8DnCcjjzmcc6NYnxWq3nExVQsWJZ06s0+7 j6Nx+dRbyp/kdPpSCB28C5J+Bn0K5u9MYF6hJ8bUva2K/1KOM2l6SO2jjA5Cje6uSPpw6E/njoDp6 2lO0Em1UwujFOKDvmy2ADwdsOeM0tiPoyA8MXnuFID40mD+FrhnMelVM8MMT1R2BRExkqPme2dgrB Kb8R61jw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v1WaI-00000003iSJ-29Rl; Wed, 24 Sep 2025 20:59:30 +0000 Received: from mail-westeuropeazlp170110003.outbound.protection.outlook.com ([2a01:111:f403:c201::3] helo=AS8PR04CU009.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1v1WaG-00000003iQf-2XfD for linux-arm-kernel@lists.infradead.org; Wed, 24 Sep 2025 20:59:29 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=kjQ66bWB17+HxUdOg27qUK1968XXgxlw/PdOwlik7BzV+/1hdyT92MHP8n4ryYSmGC57ylxTSrcKNJtY0O13ZVC3Q/llntMaKyuPnE6SIk/awfqKFZQdLdtTVym4HO0d9Vhd/LQw/2gV17dk9TdkPUVorQYR+LHJNpavAvslVJ1uIRPq8dF3l09f5ek2N81kzFjIUwb7C0eukGL+EcjPOo5Ljc5lqF+S9FSkZDIz55J06C9CqrxKnhiPu88m2Giib2ei3hFUzaF+AaIPd7E+xdhhT00NfgfXllZdYbmm9VlXAO0vVe73qaNB4HI70xbvQQq6ucJYI8LeWw/zj3AJfQ== 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=qLQwVc1w/sS3cRfltjv8ih4BvpnDmQnaS6OQNsdhaKA=; b=nxxcYB3w5y1fsavZ5R4f3LXrWUdXk96tdxuVAnxkxq43zzD4/CzjoaShDtbhJE4TZXWlQFDjtAvlj+6cAD3GCy7fPpeoLg9DNFakKWTT+B6SpW7euMjl37aCzHGN45peREvJ5NZuACCqnEKhbLQBWBTcN0cBPqfAOoBse9KUJ3P0Pv+EOGpZE/9mz8TMY73dR0WmYReypgng0XFs1g7M5INxaKavQ+NF3dq+WcKuBloxBEOj0P2s2blLLAQtN5cUqxLX7IyrvHwifMk/I3pYHeDKXvZARsh4d+B4xvVXzc8jD/ZqC8MFMhfx/0v08yC/qlzJGdHhZ28JhndVdwVqZw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nxp.com; dmarc=pass action=none header.from=nxp.com; dkim=pass header.d=nxp.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nxp.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=qLQwVc1w/sS3cRfltjv8ih4BvpnDmQnaS6OQNsdhaKA=; b=ktoy/pkF9590GeG8549G6o+6e8+JhIEQEYhZW+xhYz7iSj7SHjwAEsQU425+ZPW3rSgiHmoRt+o1J+XFGP6ZhyCa9rvXZRFDSBXU41qtHGyl5oDQKiAeRQgWQGhWGtZMqO5hghwVZx7ZYcC1hBBfwfCjH+4oLM8/Q0Zups6SusD8Vo96GKskWbMDtbA1expMDE5IGtyQvFAF41flYN+GOrPNB5rqe3dRwPNmix4eR/NQhsntVNspme9e+Kcx4XGOUphjhFwfUuYRxB5BU2sIBfzjji8DiuGRahz/tmlCrBVdWD58Nxx8wK07EfoXL9SdZNzzlFplAsKVYG75d3+0KQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nxp.com; Received: from AS4PR04MB9621.eurprd04.prod.outlook.com (2603:10a6:20b:4ff::22) by AS5PR04MB11419.eurprd04.prod.outlook.com (2603:10a6:20b:6c4::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9160.10; Wed, 24 Sep 2025 20:59:20 +0000 Received: from AS4PR04MB9621.eurprd04.prod.outlook.com ([fe80::a84d:82bf:a9ff:171e]) by AS4PR04MB9621.eurprd04.prod.outlook.com ([fe80::a84d:82bf:a9ff:171e%4]) with mapi id 15.20.9160.008; Wed, 24 Sep 2025 20:59:20 +0000 Date: Wed, 24 Sep 2025 16:59:11 -0400 From: Frank Li To: Bjorn Helgaas Cc: Richard Zhu , jingoohan1@gmail.com, l.stach@pengutronix.de, lpieralisi@kernel.org, kwilczynski@kernel.org, mani@kernel.org, robh@kernel.org, bhelgaas@google.com, shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, imx@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v6 1/4] PCI: dwc: Remove the L1SS check before putting the link into L2 Message-ID: References: <20250924072324.3046687-2-hongxing.zhu@nxp.com> <20250924194457.GA2131297@bhelgaas> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250924194457.GA2131297@bhelgaas> X-ClientProxiedBy: BYAPR07CA0090.namprd07.prod.outlook.com (2603:10b6:a03:12b::31) To AS4PR04MB9621.eurprd04.prod.outlook.com (2603:10a6:20b:4ff::22) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: AS4PR04MB9621:EE_|AS5PR04MB11419:EE_ X-MS-Office365-Filtering-Correlation-Id: d8c231de-b7ba-4bbf-70af-08ddfbad3b9f X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|19092799006|7416014|376014|52116014|38350700014|7053199007; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?Niygwsv5+julerpe3H+QIiKYPkS7tXifAyC0XlzFsrdqw6pP7GlsGA/ZLxFh?= =?us-ascii?Q?l+m3b88uwJ0FqsnwVI+HwBjKkLPLf97YE544KFRog7LMOTSTvfEJtT8rgM/V?= =?us-ascii?Q?uALIaXGa0pV2QaU6T2AlCyZxrASm/CugjcMMptXLqPZy/U4eZAn5eo/6pL2D?= =?us-ascii?Q?yZ9lbri7JXTy5KtTj7uQ9KSHeM6MAvHlJc9KfLn3ZyhjvyH6f57Y01qc+3hM?= =?us-ascii?Q?/Y0pLL3+NE0KmRPufpjlGQUO7v2UTgmj4UW4V6q8lvwM15a39faGoOaU8HKv?= =?us-ascii?Q?PZGsTR/2QD9nrZDtLvPrJs3QkgmJ0/9ekPZ320+gORLW+L+WFzs8ZuCiV8ib?= =?us-ascii?Q?RQNwyLrf+mfpHAwbR2EBRh5A6lESfk9+6/ZgQwgMF0fZIKTf+qNUhgFscaLC?= =?us-ascii?Q?sJpQchNThX9ilfSJAH6q78+uw8wty6Zj6Pnsnm8exwQrXt3kpCCrxeaoUhzC?= =?us-ascii?Q?coPgrh/MxyW3eKlCI9ywM/B0rAlYdLAeqIy8yVEiGD4FjadvXVPk0USMSgqy?= =?us-ascii?Q?3iJuTl8B4pBmf7z2Qb9m/nwi8oCG4Prcfh42ku+YGX0hHnGoEuMTTXPCLLgj?= =?us-ascii?Q?f3bKloFKZngWdDVJC3afteHzg5SAOeHNln0RMREOvUR4RhkPSCprtLbyVTea?= =?us-ascii?Q?Jub6OOr5LDPbvTO/3EULKp02YOE9zb9c0f2IkB5Q9VVp4TMXyAA9/rKCr+X2?= =?us-ascii?Q?qZYDZ4CzrzWRbf5p9P/xv4sQjIEx/zs5fSv3W/wwbXKkyJ7gQ38p6L3w4pG+?= =?us-ascii?Q?krEfhgYFCfhLPds2OyGRNPHwHvZ7JEyAcghdeeAVmMcqZoFRj7j/KvQiDwdf?= =?us-ascii?Q?CR+kKZFmPz3s5sZVLpRbvgoOLSvBApYoa0XnS4Ir/MW0q6s01AHwm9dftZEO?= =?us-ascii?Q?JHRpyYjwKyYhGDEJ/w7Z6yA84xoZKUZawq1hnjBQRMKMJZRySzg5/aokUIr6?= =?us-ascii?Q?MKAv9IsGkNuTVii/eUX9mJZsAGUc0v45kxui2SNcIEe5T52knYO2ih9dZGlN?= =?us-ascii?Q?QvHcdYvqUkLDjCNwPJF5mdVOe+WJOSX/ffa0mH2YKgpN54A5y5pHxebnpNk2?= =?us-ascii?Q?DCPX2d7ZlN0HZtr20dXEk7UbQNRHGLxBAzsiN9WlI3XsAdm4f0rnH4sPn/ZF?= =?us-ascii?Q?VhZBIJYoXbh/WtGxXsH9VXlAsEHbujNTBp3f0Rvtsfl8QGZ/NV7NVp4Cu9Bs?= =?us-ascii?Q?3lQyxz08CNbqMxBchwefSxkaSBHFWxYt+8yhXrM3DlrrwyqLMuX87uHUR/KE?= =?us-ascii?Q?hluUMzELDaSRQRiaNOaWffUpYZp9e7vxEJi4qpbm6e/0ieGXdbTma106FmeE?= =?us-ascii?Q?UD5MTNINm3ZTi8xxEBCsm7lSgNg9zaTR/K8TvQY68e3B7/UMygyUi4Wd//7y?= =?us-ascii?Q?mXlW3HN+BS+UuSv7YbLbmDIDmdlHyXxuDYeZNcJy0fJ/DBv6GlcY5oAbNbGX?= =?us-ascii?Q?7CNo53jChGfkFBCkiyYI+LzILSAPbOZkW89HadXJQJnIuxSVQA3Iqw=3D=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:AS4PR04MB9621.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(1800799024)(19092799006)(7416014)(376014)(52116014)(38350700014)(7053199007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?+srY92DvnjorscKXKf0v51KGgSRfd28rxaGqDSDlYf9s/UNpYC92rPl+TqE2?= =?us-ascii?Q?I0f1gy5UsgxMyqY6BjtA4q5ofC+eKEnr9R514ThBLoFFknm/apIkkawGWVrH?= =?us-ascii?Q?clwqKXisAtg3stxyriizMxjzVCDLGrVUrf1RxtQxDJIGhsEJc+HLED6GY4i5?= =?us-ascii?Q?vdyz/G5ORBL5Cefdo202owMaACmv6vZX/HltFYYOSyA19FF4v3fB/V7NRcEO?= =?us-ascii?Q?hbMJMG3l214F9/dM8j5VzpeR8ZERz/iAhEY/ftYHeRcbcwd9GwewMo+xbPiy?= =?us-ascii?Q?prCLALGKsPvbtvhRylwb53zIEqZjTYZJYpmlODUEMc2RDPyWsUA0wxUKYFMu?= =?us-ascii?Q?afDIraa+ZL75E4TYbzLmEUl6js2pGDJmhfY/KiczGlQtPDNnpBs7BElHyUxS?= =?us-ascii?Q?pMI099OKiQoCuOsDt6FaWF2dZfoGR+4YZSdbhF5fxF/RAljGyFzYQaBRHUok?= =?us-ascii?Q?7M/vya4C5CekzjO9CWK+mkKeEz4IN+umLhaNeI9UKq8VGO6rRNvxqWDTqql8?= =?us-ascii?Q?QolpxFXrlRDfpUhV23aYUPGnONs1TJ9ZRmb/iiYHe8xdUnv2VRG2uqzwK7lf?= =?us-ascii?Q?mJ7qhy823ZJUXGUMkCk5WH/4WqaF5b+KDCGymRGZobaOipzsaL5pGgxrOhN9?= =?us-ascii?Q?5MazVAmLKz6FiCFoXxzE37fkAZe79rWEjfoZ+iPCoMSQpinQrfl/+PbQ4cU8?= =?us-ascii?Q?gJDKgf1WaTh4zuhJ5An8gO/sWhZMLRPD9NPtN1zKY8HDnihW2av0eBGbDZBE?= =?us-ascii?Q?HljT39B6qnqTzgydT0b/97AMi/sXYwuY+Sa9Qxv9Cw/dUJnbYgLnpC6rv/en?= =?us-ascii?Q?gDdBCJ6ZZn9v/8pDVCHFzYwmsA58OCLf7zVZi9KXl+m4+ujCHx7kbiEZ2cLo?= =?us-ascii?Q?slkO4d+5AnMCcAc+ttWOw+dAbbfFDPKkpNZzHt3PU1S2nnO+/hqYjMJ2ewya?= =?us-ascii?Q?H42Tr0NDQspmIR31vd7r1dtjYB/0IdCo6jTeIq0Bo+pH7YMuzqNXQwDyQp67?= =?us-ascii?Q?2ZPBdSN4ToC+bDaF9gUW9A0mGlsHdAfbJ25nPLKcPDj+1uu8hscVn7Mxdls7?= =?us-ascii?Q?B6ogKUDTFKPJb6doPZo3Z3dVJUXk4NWZTxZ26aMbvI7psLq3tWRVAf2th6Wg?= =?us-ascii?Q?6XSy3P59SDK1JnQBKDAbsX0YkY+AgrCNtF/aN++S2zwq9iN1Xc82GrAuEBJS?= =?us-ascii?Q?Sj/uGGTUULU6YvjmXvfW5R4bCkjnqABQnT+y4goFMIaWJQ/wsvJtKmTNp9NI?= =?us-ascii?Q?fbe/4PBZlmZR2uvfHB3rdliQox9GsUAll/fntLaVMPdBAnPoK/8qn84K4rDn?= =?us-ascii?Q?lQbZXOLO/5n30J4Tu9c59cYV7tqfw/PDaQfA/u6QVZmZ4clJBAYF0uyDXRAu?= =?us-ascii?Q?DOnWNa7IWyB0AU9gxMvnAA64uBaMwf0ZBMXdMs0FUBzgnH3fA4gHoId/MHXL?= =?us-ascii?Q?oY05cb/5Zvspq8ElPab3N0BOg8qAIsy8IBSVmF2ZmwrVG+HTbT2wrPPSj+ND?= =?us-ascii?Q?/BohH+pDR1XL/INmAGUPs0FZXO8hHvc+WjLww8CZtDqAr4W29dZkM0Tu6h1q?= =?us-ascii?Q?xB6SDWiU/45ezRpzNAjwDtlGYv+qZTNLD9ocd6t+?= X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-Network-Message-Id: d8c231de-b7ba-4bbf-70af-08ddfbad3b9f X-MS-Exchange-CrossTenant-AuthSource: AS4PR04MB9621.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Sep 2025 20:59:20.7559 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: CA752QsTFDUdifi43BQALQg4Ti1jr1AY0wbAkMCXCc3X84vi9bRHRn/DNItXZBi7BlKyLL910lWNjna1oZxkxw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: AS5PR04MB11419 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250924_135928_653755_52ABBE07 X-CRM114-Status: GOOD ( 26.50 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Sep 24, 2025 at 02:44:57PM -0500, Bjorn Helgaas wrote: > On Wed, Sep 24, 2025 at 03:23:21PM +0800, Richard Zhu wrote: > > The ASPM configuration shouldn't leak out here. Remove the L1SS check > > during L2 entry. > > I'm all in favor of removing this code if possible, but we need to > explain why this is safe. The L1SS check was added for some reason, > and we need to explain why that reason doesn't apply. That's original discussion https://lore.kernel.org/linux-pci/20230720160738.GC48270@thinkpad/ "To be precise, NVMe driver will shutdown the device if there is no ASPM support and keep it in low power mode otherwise (there are other cases as well but we do not need to worry). But here you are not checking for ASPM state in the suspend path, and just forcing the link to be in L2/L3 (thereby D3Cold) even though NVMe driver may expect it to be in low power state like ASPM/APST. So you should only put the link to L2/L3 if there is no ASPM support. Otherwise, you'll ending up with bug reports when users connect NVMe to it. - Mani" Frank > > > Cc: stable@vger.kernel.org > > Fixes: 4774faf854f5 ("PCI: dwc: Implement generic suspend/resume functionality") > > Suggested-by: Bjorn Helgaas > > Signed-off-by: Richard Zhu > > --- > > drivers/pci/controller/dwc/pcie-designware-host.c | 8 -------- > > 1 file changed, 8 deletions(-) > > > > diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c > > index 952f8594b501..9d46d1f0334b 100644 > > --- a/drivers/pci/controller/dwc/pcie-designware-host.c > > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c > > @@ -1005,17 +1005,9 @@ static int dw_pcie_pme_turn_off(struct dw_pcie *pci) > > > > int dw_pcie_suspend_noirq(struct dw_pcie *pci) > > { > > - u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); > > u32 val; > > int ret; > > > > - /* > > - * If L1SS is supported, then do not put the link into L2 as some > > - * devices such as NVMe expect low resume latency. > > - */ > > - if (dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKCTL) & PCI_EXP_LNKCTL_ASPM_L1) > > - return 0; > > - > > if (pci->pp.ops->pme_turn_off) { > > pci->pp.ops->pme_turn_off(&pci->pp); > > } else { > > -- > > 2.37.1 > >