Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752803AbdLEWWR (ORCPT ); Tue, 5 Dec 2017 17:22:17 -0500 Received: from esa1.hgst.iphmx.com ([68.232.141.245]:34035 "EHLO esa1.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752073AbdLEWWM (ORCPT ); Tue, 5 Dec 2017 17:22:12 -0500 X-IronPort-AV: E=Sophos;i="5.45,365,1508774400"; d="scan'208";a="166955082" From: Bart Van Assche To: "beanhuo@micron.com" , "linux-scsi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" CC: "gregkh@linuxfoundation.org" , "vinholikatti@gmail.com" Subject: Re: UFS utilities Thread-Topic: UFS utilities Thread-Index: AQHTbhd9Zn8P8X2ekE+hDwFG8qg76Q== Date: Tue, 5 Dec 2017 22:22:09 +0000 Message-ID: <1512512528.2660.40.camel@wdc.com> References: <1511811323.2993.13.camel@wdc.com> In-Reply-To: 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=Bart.VanAssche@wdc.com; x-originating-ip: [199.255.44.171] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;CY1PR0401MB1535;20:7daDGVMYWj0ZPoPmxSnL5wQ18mRoMsSDA9SwhTh29Sw5VdGsiWKFF6yIoAF642LSt+aDutiltkOSMwyCf66EmSYpE9OMNTR8T7vhi7SSK0/OMHqag742vhoor7IT8N2DdsDFU3KIV+VGUtj3cxooENIJZmozb3oVblCJsXDQaHQ= x-ms-exchange-antispam-srfa-diagnostics: SSOS; x-ms-office365-filtering-ht: Tenant x-ms-office365-filtering-correlation-id: b02d1653-0b59-4abe-e82a-08d53c2ea008 x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(4534020)(4602075)(4627115)(201703031133081)(201702281549075)(48565401081)(5600026)(4604075)(2017052603286);SRVR:CY1PR0401MB1535; x-ms-traffictypediagnostic: CY1PR0401MB1535: wdcipoutbound: EOP-TRUE x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:; x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(6040450)(2401047)(8121501046)(5005006)(3231022)(93006095)(93001095)(3002001)(10201501046)(6055026)(6041248)(20161123562025)(20161123555025)(201703131423075)(201702281528075)(201703061421075)(201703061406153)(20161123558100)(20161123560025)(20161123564025)(6072148)(201708071742011);SRVR:CY1PR0401MB1535;BCL:0;PCL:0;RULEID:(100000803101)(100110400095);SRVR:CY1PR0401MB1535; x-forefront-prvs: 0512CC5201 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(346002)(376002)(366004)(24454002)(377424004)(189003)(199004)(103116003)(478600001)(25786009)(8676002)(2900100001)(101416001)(36756003)(6116002)(3846002)(102836003)(72206003)(81166006)(6512007)(105586002)(33646002)(81156014)(66066001)(106356001)(3480700004)(8936002)(221733001)(97736004)(229853002)(39060400002)(99286004)(2501003)(2950100002)(3660700001)(3280700002)(6246003)(2906002)(7736002)(76176011)(86362001)(6436002)(110136005)(54906003)(14454004)(6506006)(305945005)(68736007)(316002)(77096006)(7116003)(2201001)(6486002)(5660300001)(4326008)(53936002);DIR:OUT;SFP:1102;SCL:1;SRVR:CY1PR0401MB1535;H:CY1PR0401MB1536.namprd04.prod.outlook.com;FPR:;SPF:None;PTR:InfoNoRecords;MX:1;A:1;LANG:en; spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="utf-8" Content-ID: <690567FE5ED7F74F9F70724E76AFB8AB@namprd04.prod.outlook.com> MIME-Version: 1.0 X-OriginatorOrg: wdc.com X-MS-Exchange-CrossTenant-Network-Message-Id: b02d1653-0b59-4abe-e82a-08d53c2ea008 X-MS-Exchange-CrossTenant-originalarrivaltime: 05 Dec 2017 22:22:09.3112 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b61c8803-16f3-4c35-9b17-6f65f441df86 X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY1PR0401MB1535 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by nfs id vB5MMMrm029838 Content-Length: 613 Lines: 13 On Mon, 2017-12-04 at 15:20 +0000, Bean Huo (beanhuo) wrote: > Also, is it possible bypass SCSI stacks and go into directly UFS stack? Hello Bean, Sorry but I think it would be wrong to bypass the block layer when submitting UFS commands. My understanding is that UFS devices are used in systems where power management functionality is important (see also Documentation/power). If the block layer would be bypassed then the power management support that exists in the block layer will have to be reimplemented in UFS devices. That would be a duplicate effort. I'm not sure that we want such duplication. Bart.