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 X-Spam-Level: X-Spam-Status: No, score=-4.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73631C282C4 for ; Tue, 22 Jan 2019 09:17:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 394B52085A for ; Tue, 22 Jan 2019 09:17:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=nxp.com header.i=@nxp.com header.b="tjP1ObPT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727505AbfAVJRd (ORCPT ); Tue, 22 Jan 2019 04:17:33 -0500 Received: from mail-eopbgr00079.outbound.protection.outlook.com ([40.107.0.79]:8028 "EHLO EUR02-AM5-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727318AbfAVJRb (ORCPT ); Tue, 22 Jan 2019 04:17:31 -0500 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=y2gEnXpuSaxVieE6UjZz4Fp5+aDJ6SM0GE/M8H5jFhI=; b=tjP1ObPTsgy4psKujFFWkvt0elx/sa6XDRXkl9X1Z2V3QnelOrhXFhcQZtZxVDV53LODqw1eR1fd4KiB4kAc8HDpNcBrNVRGaHHSkOY277LDnSIgRk2UuoQb7yDeKeM7SR9tdCtvCkG14Njo8nObxEQVfCTwnSFCGWkDX7XM7SU= Received: from VI1PR04MB5533.eurprd04.prod.outlook.com (20.178.122.159) by VI1PR04MB4767.eurprd04.prod.outlook.com (20.177.48.212) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.1537.31; Tue, 22 Jan 2019 09:17:23 +0000 Received: from VI1PR04MB5533.eurprd04.prod.outlook.com ([fe80::92d:bf44:9c1d:b907]) by VI1PR04MB5533.eurprd04.prod.outlook.com ([fe80::92d:bf44:9c1d:b907%6]) with mapi id 15.20.1537.031; Tue, 22 Jan 2019 09:17:23 +0000 From: Leonard Crestez To: =?iso-8859-1?Q?Uwe_Kleine-K=F6nig?= , Ulf Hansson CC: Lorenzo Pieralisi , "Lukas F . Hartmann" , Lucas Stach , Richard Zhu , "linux-pci@vger.kernel.org" , dl-linux-imx , "kernel@pengutronix.de" , Shawn Guo , "linux-arm-kernel@lists.infradead.org" , "Rafael J. Wysocki" , Kevin Hilman , "linux-pm@vger.kernel.org" , Viresh Kumar , Jon Hunter Subject: Re: [PATCH 1/2] PCI: imx: Fix probe failure without power domain Thread-Topic: [PATCH 1/2] PCI: imx: Fix probe failure without power domain Thread-Index: AQHUsdumnhpLtdU11UCqN+1L30Gg6Q== Date: Tue, 22 Jan 2019 09:17:22 +0000 Message-ID: References: <375a852ae9170a5f8f53fdd364a7fb7ea642e89c.1548110502.git.leonard.crestez@nxp.com> <20190122071251.tgdwnunxksa45n5q@pengutronix.de> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: spf=none (sender IP is ) smtp.mailfrom=leonard.crestez@nxp.com; x-originating-ip: [192.88.166.1] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;VI1PR04MB4767;6:yc2e1vqzP9e5UVUwvOwnjTo/WKXJnfqGi7jU0qcLPvbA7IUgC8RPbCfSiOBa7wl8RELTFw65pFqQGgQGfbrlHculVjYf46gGZo7vA/kV8GeaNSUeW906WjTQPeY4cFnzYRlRlPcp3kN8Cz+ufLRWmFkxsrezrsYU7QuEUEpYT7jxQ+nlC6HS+BX8BH9b6HgmSbRCiCKe+wHrU9tt+3T5fdOl0p4919eyAt8VIv/urzA2+VOjZMR65uxNZYkyVmLshXAD0CRAjw/UJWNfTqsTPLF+AXPL5RaVLdhVLPk4puu2/jmdIYY+zp1dTgWyLPmIfGmcbWL4MZiQ+VdUN0WyY7JIK+rCG8V1s+NmrL88e3XwZpvlFHRhaYz2AMk81+vD7fLJqt9K+x271+xgTFTOeDhUTUULuPd/EQUTVaaS2DwRKaTX3SwDLsk4IAtzva7gHP8IhQqDkn2qodbUIVz3FQ==;5:QeCIyRJMsjTNqOOilcXuDtLHGZf/V4a4buqE9KsFO7rIQNL+fNBr/jC0gDpsoBXsXH6IAUNzdtttUzldbatLY6OGPqGTi5qEDTlQXK3xYFKTWeQAF9h32kCHEM33p/JnJm+422ccth5Whz5WDK3fnKjMZAI4o7V0PpOd1UPuqNeFd1V4lif7EASWGLiBmnAcJjL1rygk61oG5hpkdW+EJw==;7:2cBkwZ5i/Y673Zdc/vNzHctT/DvbUirgxdUh5uFVlddC0L3kvYJFmMWfIpm3OAU2OW1H8frvvGtJHiex6UlhzN3/e8cpgdJ1eHFwagXkiopZp3tS+uhUEXPI9MrXrtpdE0NnNpa3WhHDuMmQhMI6jg== x-ms-exchange-antispam-srfa-diagnostics: SOS; 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received-spf: None (protection.outlook.com: nxp.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: sQ6CajqnPJ44ICfHlYkijwl/xA3209Kef7br7wmNz8DqqYIVzjUvQdWpe9/LxkqUrEUZWAGRk3lmIaFLyoJAUmkioCuBCj3/0dO5M/OL8wEMkSS1w/27CbCa6uASF4H23i/h1cXiTc7BtxzgYRXIUI2gbVayXU3TnKWXR4mtonHkF0Zu0iHHwbPZtO/C8p0nFKCtaZ9A15IdsEg5BH40aMvZduEQY1CYkCqUkkl5Q2eox3PK72PRl5TP4i0RNSMifxY9dgGVRpPzh0SKrN3DBcl0Dkcf2ZHuR7x1Tt+uxA4jjjMlHRLn7S1IkYUBcks7pbr8wI97DzwQXcBefEvViw/1LuzKP2q3Ti6SWJnIz6tVMEfdBytzBSaQZmNck/ZxSfaQrLN2Nl/F/1vbTwqR3dTo2v5lGWB4lRywcQNT/EI= spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-Network-Message-Id: e528650c-d66b-4c8f-fb44-08d6804a6b06 X-MS-Exchange-CrossTenant-originalarrivaltime: 22 Jan 2019 09:17:22.9207 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1PR04MB4767 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On 1/22/2019 9:12 AM, Uwe Kleine-K=F6nig wrote:=0A= > On Mon, Jan 21, 2019 at 10:50:04PM +0000, Leonard Crestez wrote:=0A= >> On chips without a separate power domain for PCI (such as 6q/6qp) the=0A= >> imx6_pcie_attach_pd function incorrectly returns an error.=0A= >>=0A= >> Fix by returning 0 if dev_pm_domain_attach_by_name doesn't find=0A= >> anything.=0A= >>=0A= >> Fixes: 3f7cceeab895 ("PCI: imx: Add multi-pd support")=0A= >>=0A= >> diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/control= ler/dwc/pci-imx6.c=0A= >> @@ -308,10 +308,13 @@ static int imx6_pcie_attach_pd(struct device *dev)= =0A= >> return 0;=0A= >> =0A= >> imx6_pcie->pd_pcie =3D dev_pm_domain_attach_by_name(dev, "pcie");=0A= >> if (IS_ERR(imx6_pcie->pd_pcie))=0A= >> return PTR_ERR(imx6_pcie->pd_pcie);=0A= >> + /* Do nothing when power domain missing */=0A= >> + if (!imx6_pcie->pd_pcie)=0A= >> + return 0;=0A= > =0A= > As I said in the mail that proposed this patch for testing: I think it=0A= > would be better to change dev_pm_domain_attach_by_name to not return an= =0A= > error indication by returning NULL or an ERR_PTR value. (Or change=0A= > device_link_add to accept NULL if NULL is a dummy value.)=0A= > =0A= > Just repeating it here to have it near the actual patch.=0A= =0A= Link to that previous discussion: =0A= http://lists.infradead.org/pipermail/linux-arm-kernel/2019-January/626859.h= tml=0A= =0A= I'm not sure what you mean. Should dev_pm_domain_attach_by_name return =0A= ERR_PTR(-ENOENT) for name not found? It would still require special =0A= handling for callers.=0A= =0A= The device_link_add function already returns NULL if the consumer or =0A= supplier is NULL but that's also the only way it signals failure. Maybe =0A= that function should be adjusted to return ERR_PTR instead?=0A= =0A= Changing core API for a driver bug seems inappropriate.=0A= =0A= The current imx6_pcie_attach_pd code is complicated because it tries to =0A= distinguish between "multi pd" and "no pd / single pd". I wish there was = =0A= a way for these PM_RUNTIME device_links to be setup automatically in =0A= core and have multi-PD behave the same as a single PD.=0A= =0A= There aren't many multi-PD users but commit 6494a9ad86de ("usb: xhci: =0A= tegra: Add genpd support") seems to do pretty much the same thing.=0A= =0A= --=0A= Regards,=0A= Leonard=0A=